Merge pull request #2368 from wpaulino/inbound-anchors-manual-acceptance
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 30eab9066fd0b4190ef65167d8e82c98c51c9be1..a03f11d57443f340713909cac761e057d7637ead 100644 (file)
@@ -19,7 +19,7 @@
 
 use bitcoin::blockdata::block::BlockHeader;
 use bitcoin::blockdata::transaction::Transaction;
-use bitcoin::blockdata::constants::genesis_block;
+use bitcoin::blockdata::constants::{genesis_block, ChainHash};
 use bitcoin::network::constants::Network;
 
 use bitcoin::hashes::Hash;
@@ -40,7 +40,7 @@ use crate::events::{Event, EventHandler, EventsProvider, MessageSendEvent, Messa
 // Since this struct is returned in `list_channels` methods, expose it here in case users want to
 // construct one themselves.
 use crate::ln::{inbound_payment, PaymentHash, PaymentPreimage, PaymentSecret};
-use crate::ln::channel::{Channel, ChannelError, ChannelUpdateStatus, UpdateFulfillCommitFetch};
+use crate::ln::channel::{Channel, ChannelContext, ChannelError, ChannelUpdateStatus, ShutdownResult, UpdateFulfillCommitFetch, OutboundV1Channel, InboundV1Channel};
 use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
 #[cfg(any(feature = "_test_utils", test))]
 use crate::ln::features::InvoiceFeatures;
@@ -50,13 +50,13 @@ use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParame
 use crate::ln::msgs;
 use crate::ln::onion_utils;
 use crate::ln::onion_utils::HTLCFailReason;
-use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError, MAX_VALUE_MSAT};
+use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 #[cfg(test)]
 use crate::ln::outbound_payment;
 use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment};
 use crate::ln::wire::Encode;
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, ChannelSigner, WriteableEcdsaChannelSigner};
-use crate::util::config::{UserConfig, ChannelConfig};
+use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
 use crate::util::scid_utils::fake_scid;
 use crate::util::string::UntrustedString;
@@ -112,6 +112,8 @@ pub(super) enum PendingHTLCRouting {
                phantom_shared_secret: Option<[u8; 32]>,
        },
        ReceiveKeysend {
+               /// This was added in 0.0.116 and will break deserialization on downgrades.
+               payment_data: Option<msgs::FinalOnionHopData>,
                payment_preimage: PaymentPreimage,
                payment_metadata: Option<Vec<u8>>,
                incoming_cltv_expiry: u32, // Used to track when we should expire pending HTLCs that go unclaimed
@@ -129,6 +131,9 @@ pub(super) struct PendingHTLCInfo {
        /// may overshoot this in either case)
        pub(super) outgoing_amt_msat: u64,
        pub(super) outgoing_cltv_value: u32,
+       /// The fee being skimmed off the top of this HTLC. If this is a forward, it'll be the fee we are
+       /// skimming. If we're receiving this HTLC, it's the fee that our counterparty skimmed.
+       pub(super) skimmed_fee_msat: Option<u64>,
 }
 
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
@@ -208,6 +213,8 @@ struct ClaimableHTLC {
        total_value_received: Option<u64>,
        /// The sender intended sum total of all MPP parts specified in the onion
        total_msat: u64,
+       /// The extra fee our counterparty skimmed off the top of this HTLC.
+       counterparty_skimmed_fee_msat: Option<u64>,
 }
 
 /// A payment identifier used to uniquely identify a payment to LDK.
@@ -359,8 +366,6 @@ pub enum FailureCode {
        IncorrectOrUnknownPaymentDetails = 0x4000 | 15,
 }
 
-type ShutdownResult = (Option<(OutPoint, ChannelMonitorUpdate)>, Vec<(HTLCSource, PaymentHash, PublicKey, [u8; 32])>);
-
 /// Error type returned across the peer_state mutex boundary. When an Err is generated for a
 /// Channel, we generally end up with a ChannelError::Close for which we have to close the channel
 /// immediately (ie with no further calls on it made). Thus, this step happens inside a
@@ -497,15 +502,34 @@ struct ClaimablePayments {
        pending_claiming_payments: HashMap<PaymentHash, ClaimingPayment>,
 }
 
-/// Events which we process internally but cannot be procsesed immediately at the generation site
-/// for some reason. They are handled in timer_tick_occurred, so may be processed with
-/// quite some time lag.
+/// Events which we process internally but cannot be processed immediately at the generation site
+/// usually because we're running pre-full-init. They are handled immediately once we detect we are
+/// running normally, and specifically must be processed before any other non-background
+/// [`ChannelMonitorUpdate`]s are applied.
 enum BackgroundEvent {
-       /// Handle a ChannelMonitorUpdate
+       /// Handle a ChannelMonitorUpdate which closes the channel. This is only separated from
+       /// [`Self::MonitorUpdateRegeneratedOnStartup`] as the maybe-non-closing variant needs a public
+       /// key to handle channel resumption, whereas if the channel has been force-closed we do not
+       /// need the counterparty node_id.
+       ///
+       /// Note that any such events are lost on shutdown, so in general they must be updates which
+       /// are regenerated on startup.
+       ClosingMonitorUpdateRegeneratedOnStartup((OutPoint, ChannelMonitorUpdate)),
+       /// Handle a ChannelMonitorUpdate which may or may not close the channel and may unblock the
+       /// channel to continue normal operation.
+       ///
+       /// In general this should be used rather than
+       /// [`Self::ClosingMonitorUpdateRegeneratedOnStartup`], however in cases where the
+       /// `counterparty_node_id` is not available as the channel has closed from a [`ChannelMonitor`]
+       /// error the other variant is acceptable.
        ///
        /// Note that any such events are lost on shutdown, so in general they must be updates which
        /// are regenerated on startup.
-       MonitorUpdateRegeneratedOnStartup((OutPoint, ChannelMonitorUpdate)),
+       MonitorUpdateRegeneratedOnStartup {
+               counterparty_node_id: PublicKey,
+               funding_txo: OutPoint,
+               update: ChannelMonitorUpdate
+       },
 }
 
 #[derive(Debug)]
@@ -515,13 +539,31 @@ pub(crate) enum MonitorUpdateCompletionAction {
        /// this payment. Note that this is only best-effort. On restart it's possible such a duplicate
        /// event can be generated.
        PaymentClaimed { payment_hash: PaymentHash },
-       /// Indicates an [`events::Event`] should be surfaced to the user.
-       EmitEvent { event: events::Event },
+       /// Indicates an [`events::Event`] should be surfaced to the user and possibly resume the
+       /// operation of another channel.
+       ///
+       /// This is usually generated when we've forwarded an HTLC and want to block the outbound edge
+       /// from completing a monitor update which removes the payment preimage until the inbound edge
+       /// completes a monitor update containing the payment preimage. In that case, after the inbound
+       /// edge completes, we will surface an [`Event::PaymentForwarded`] as well as unblock the
+       /// outbound edge.
+       EmitEventAndFreeOtherChannel {
+               event: events::Event,
+               downstream_counterparty_and_funding_outpoint: Option<(PublicKey, OutPoint, RAAMonitorUpdateBlockingAction)>,
+       },
 }
 
 impl_writeable_tlv_based_enum_upgradable!(MonitorUpdateCompletionAction,
        (0, PaymentClaimed) => { (0, payment_hash, required) },
-       (2, EmitEvent) => { (0, event, upgradable_required) },
+       (2, EmitEventAndFreeOtherChannel) => {
+               (0, event, upgradable_required),
+               // LDK prior to 0.0.116 did not have this field as the monitor update application order was
+               // required by clients. If we downgrade to something prior to 0.0.116 this may result in
+               // monitor updates which aren't properly blocked or resumed, however that's fine - we don't
+               // support async monitor updates even in LDK 0.0.116 and once we do we'll require no
+               // downgrades to prior versions.
+               (1, downstream_counterparty_and_funding_outpoint, option),
+       },
 );
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -538,19 +580,66 @@ impl_writeable_tlv_based_enum!(EventCompletionAction,
        };
 );
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+/// If something is blocked on the completion of an RAA-generated [`ChannelMonitorUpdate`] we track
+/// the blocked action here. See enum variants for more info.
+pub(crate) enum RAAMonitorUpdateBlockingAction {
+       /// A forwarded payment was claimed. We block the downstream channel completing its monitor
+       /// update which removes the HTLC preimage until the upstream channel has gotten the preimage
+       /// durably to disk.
+       ForwardedPaymentInboundClaim {
+               /// The upstream channel ID (i.e. the inbound edge).
+               channel_id: [u8; 32],
+               /// The HTLC ID on the inbound edge.
+               htlc_id: u64,
+       },
+}
+
+impl RAAMonitorUpdateBlockingAction {
+       #[allow(unused)]
+       fn from_prev_hop_data(prev_hop: &HTLCPreviousHopData) -> Self {
+               Self::ForwardedPaymentInboundClaim {
+                       channel_id: prev_hop.outpoint.to_channel_id(),
+                       htlc_id: prev_hop.htlc_id,
+               }
+       }
+}
+
+impl_writeable_tlv_based_enum!(RAAMonitorUpdateBlockingAction,
+       (0, ForwardedPaymentInboundClaim) => { (0, channel_id, required), (2, htlc_id, required) }
+;);
+
+
 /// State we hold per-peer.
 pub(super) struct PeerState<Signer: ChannelSigner> {
-       /// `temporary_channel_id` or `channel_id` -> `channel`.
+       /// `channel_id` -> `Channel`.
        ///
-       /// Holds all channels where the peer is the counterparty. Once a channel has been assigned a
-       /// `channel_id`, the `temporary_channel_id` key in the map is updated and is replaced by the
-       /// `channel_id`.
+       /// Holds all funded channels where the peer is the counterparty.
        pub(super) channel_by_id: HashMap<[u8; 32], Channel<Signer>>,
+       /// `temporary_channel_id` -> `OutboundV1Channel`.
+       ///
+       /// Holds all outbound V1 channels where the peer is the counterparty. Once an outbound channel has
+       /// been assigned a `channel_id`, the entry in this map is removed and one is created in
+       /// `channel_by_id`.
+       pub(super) outbound_v1_channel_by_id: HashMap<[u8; 32], OutboundV1Channel<Signer>>,
+       /// `temporary_channel_id` -> `InboundV1Channel`.
+       ///
+       /// Holds all inbound V1 channels where the peer is the counterparty. Once an inbound channel has
+       /// been assigned a `channel_id`, the entry in this map is removed and one is created in
+       /// `channel_by_id`.
+       pub(super) inbound_v1_channel_by_id: HashMap<[u8; 32], InboundV1Channel<Signer>>,
        /// The latest `InitFeatures` we heard from the peer.
        latest_features: InitFeatures,
        /// Messages to send to the peer - pushed to in the same lock that they are generated in (except
        /// for broadcast messages, where ordering isn't as strict).
        pub(super) pending_msg_events: Vec<MessageSendEvent>,
+       /// Map from Channel IDs to pending [`ChannelMonitorUpdate`]s which have been passed to the
+       /// user but which have not yet completed.
+       ///
+       /// Note that the channel may no longer exist. For example if the channel was closed but we
+       /// later needed to claim an HTLC which is pending on-chain, we may generate a monitor update
+       /// for a missing channel.
+       in_flight_monitor_updates: BTreeMap<OutPoint, Vec<ChannelMonitorUpdate>>,
        /// Map from a specific channel to some action(s) that should be taken when all pending
        /// [`ChannelMonitorUpdate`]s for the channel complete updating.
        ///
@@ -566,6 +655,11 @@ pub(super) struct PeerState<Signer: ChannelSigner> {
        /// to funding appearing on-chain), the downstream `ChannelMonitor` set is required to ensure
        /// duplicates do not occur, so such channels should fail without a monitor update completing.
        monitor_update_blocked_actions: BTreeMap<[u8; 32], Vec<MonitorUpdateCompletionAction>>,
+       /// If another channel's [`ChannelMonitorUpdate`] needs to complete before a channel we have
+       /// with this peer can complete an RAA [`ChannelMonitorUpdate`] (e.g. because the RAA update
+       /// will remove a preimage that needs to be durably in an upstream channel first), we put an
+       /// entry here to note that the channel with the key's ID is blocked on a set of actions.
+       actions_blocking_raa_monitor_updates: BTreeMap<[u8; 32], Vec<RAAMonitorUpdateBlockingAction>>,
        /// The peer is currently connected (i.e. we've seen a
        /// [`ChannelMessageHandler::peer_connected`] and no corresponding
        /// [`ChannelMessageHandler::peer_disconnected`].
@@ -581,6 +675,21 @@ impl <Signer: ChannelSigner> PeerState<Signer> {
                        return false
                }
                self.channel_by_id.is_empty() && self.monitor_update_blocked_actions.is_empty()
+                       && self.in_flight_monitor_updates.is_empty()
+       }
+
+       // Returns a count of all channels we have with this peer, including pending channels.
+       fn total_channel_count(&self) -> usize {
+               self.channel_by_id.len() +
+                       self.outbound_v1_channel_by_id.len() +
+                       self.inbound_v1_channel_by_id.len()
+       }
+
+       // Returns a bool indicating if the given `channel_id` matches a channel we have with this peer.
+       fn has_channel(&self, channel_id: &[u8; 32]) -> bool {
+               self.channel_by_id.contains_key(channel_id) ||
+                       self.outbound_v1_channel_by_id.contains_key(channel_id) ||
+                       self.inbound_v1_channel_by_id.contains_key(channel_id)
        }
 }
 
@@ -645,40 +754,44 @@ pub type SimpleArcChannelManager<M, T, F, L> = ChannelManager<
 /// This is not exported to bindings users as Arcs don't make sense in bindings
 pub type SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L> = ChannelManager<&'a M, &'b T, &'c KeysManager, &'c KeysManager, &'c KeysManager, &'d F, &'e DefaultRouter<&'f NetworkGraph<&'g L>, &'g L, &'h Mutex<ProbabilisticScorer<&'f NetworkGraph<&'g L>, &'g L>>, ProbabilisticScoringFeeParameters, ProbabilisticScorer<&'f NetworkGraph<&'g L>, &'g L>>, &'g L>;
 
+macro_rules! define_test_pub_trait { ($vis: vis) => {
 /// A trivial trait which describes any [`ChannelManager`] used in testing.
-#[cfg(any(test, feature = "_test_utils"))]
-pub trait AChannelManager {
-       type Watch: chain::Watch<Self::Signer>;
+$vis trait AChannelManager {
+       type Watch: chain::Watch<Self::Signer> + ?Sized;
        type M: Deref<Target = Self::Watch>;
-       type Broadcaster: BroadcasterInterface;
+       type Broadcaster: BroadcasterInterface + ?Sized;
        type T: Deref<Target = Self::Broadcaster>;
-       type EntropySource: EntropySource;
+       type EntropySource: EntropySource + ?Sized;
        type ES: Deref<Target = Self::EntropySource>;
-       type NodeSigner: NodeSigner;
+       type NodeSigner: NodeSigner + ?Sized;
        type NS: Deref<Target = Self::NodeSigner>;
-       type Signer: WriteableEcdsaChannelSigner;
-       type SignerProvider: SignerProvider<Signer = Self::Signer>;
+       type Signer: WriteableEcdsaChannelSigner + Sized;
+       type SignerProvider: SignerProvider<Signer = Self::Signer> + ?Sized;
        type SP: Deref<Target = Self::SignerProvider>;
-       type FeeEstimator: FeeEstimator;
+       type FeeEstimator: FeeEstimator + ?Sized;
        type F: Deref<Target = Self::FeeEstimator>;
-       type Router: Router;
+       type Router: Router + ?Sized;
        type R: Deref<Target = Self::Router>;
-       type Logger: Logger;
+       type Logger: Logger + ?Sized;
        type L: Deref<Target = Self::Logger>;
        fn get_cm(&self) -> &ChannelManager<Self::M, Self::T, Self::ES, Self::NS, Self::SP, Self::F, Self::R, Self::L>;
 }
+} }
 #[cfg(any(test, feature = "_test_utils"))]
+define_test_pub_trait!(pub);
+#[cfg(not(any(test, feature = "_test_utils")))]
+define_test_pub_trait!(pub(crate));
 impl<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref> AChannelManager
 for ChannelManager<M, T, ES, NS, SP, F, R, L>
 where
-       M::Target: chain::Watch<<SP::Target as SignerProvider>::Signer> + Sized,
-       T::Target: BroadcasterInterface + Sized,
-       ES::Target: EntropySource + Sized,
-       NS::Target: NodeSigner + Sized,
-       SP::Target: SignerProvider + Sized,
-       F::Target: FeeEstimator + Sized,
-       R::Target: Router + Sized,
-       L::Target: Logger + Sized,
+       M::Target: chain::Watch<<SP::Target as SignerProvider>::Signer>,
+       T::Target: BroadcasterInterface,
+       ES::Target: EntropySource,
+       NS::Target: NodeSigner,
+       SP::Target: SignerProvider,
+       F::Target: FeeEstimator,
+       R::Target: Router,
+       L::Target: Logger,
 {
        type Watch = M::Target;
        type M = M;
@@ -964,7 +1077,18 @@ where
        pending_events: Mutex<VecDeque<(events::Event, Option<EventCompletionAction>)>>,
        /// A simple atomic flag to ensure only one task at a time can be processing events asynchronously.
        pending_events_processor: AtomicBool,
+
+       /// If we are running during init (either directly during the deserialization method or in
+       /// block connection methods which run after deserialization but before normal operation) we
+       /// cannot provide the user with [`ChannelMonitorUpdate`]s through the normal update flow -
+       /// prior to normal operation the user may not have loaded the [`ChannelMonitor`]s into their
+       /// [`ChainMonitor`] and thus attempting to update it will fail or panic.
+       ///
+       /// Thus, we place them here to be handled as soon as possible once we are running normally.
+       ///
        /// See `ChannelManager` struct-level documentation for lock order requirements.
+       ///
+       /// [`ChainMonitor`]: crate::chain::chainmonitor::ChainMonitor
        pending_background_events: Mutex<Vec<BackgroundEvent>>,
        /// Used when we have to take a BIG lock to make sure everything is self-consistent.
        /// Essentially just when we're serializing ourselves out.
@@ -974,6 +1098,9 @@ where
        /// Notifier the lock contains sends out a notification when the lock is released.
        total_consistency_lock: RwLock<()>,
 
+       #[cfg(debug_assertions)]
+       background_events_processed_since_startup: AtomicBool,
+
        persistence_notifier: Notifier,
 
        entropy_source: ES,
@@ -1000,6 +1127,7 @@ pub struct ChainParameters {
 }
 
 #[derive(Copy, Clone, PartialEq)]
+#[must_use]
 enum NotifyOption {
        DoPersist,
        SkipPersist,
@@ -1023,10 +1151,20 @@ struct PersistenceNotifierGuard<'a, F: Fn() -> NotifyOption> {
 }
 
 impl<'a> PersistenceNotifierGuard<'a, fn() -> NotifyOption> { // We don't care what the concrete F is here, it's unused
-       fn notify_on_drop(lock: &'a RwLock<()>, notifier: &'a Notifier) -> PersistenceNotifierGuard<'a, impl Fn() -> NotifyOption> {
-               PersistenceNotifierGuard::optionally_notify(lock, notifier, || -> NotifyOption { NotifyOption::DoPersist })
+       fn notify_on_drop<C: AChannelManager>(cm: &'a C) -> PersistenceNotifierGuard<'a, impl Fn() -> NotifyOption> {
+               let read_guard = cm.get_cm().total_consistency_lock.read().unwrap();
+               let _ = cm.get_cm().process_background_events(); // We always persist
+
+               PersistenceNotifierGuard {
+                       persistence_notifier: &cm.get_cm().persistence_notifier,
+                       should_persist: || -> NotifyOption { NotifyOption::DoPersist },
+                       _read_guard: read_guard,
+               }
+
        }
 
+       /// Note that if any [`ChannelMonitorUpdate`]s are possibly generated,
+       /// [`ChannelManager::process_background_events`] MUST be called first.
        fn optionally_notify<F: Fn() -> NotifyOption>(lock: &'a RwLock<()>, notifier: &'a Notifier, persist_check: F) -> PersistenceNotifierGuard<'a, F> {
                let read_guard = lock.read().unwrap();
 
@@ -1274,8 +1412,14 @@ pub struct ChannelDetails {
        /// the current state and per-HTLC limit(s). This is intended for use when routing, allowing us
        /// to use a limit as close as possible to the HTLC limit we can currently send.
        ///
-       /// See also [`ChannelDetails::balance_msat`] and [`ChannelDetails::outbound_capacity_msat`].
+       /// See also [`ChannelDetails::next_outbound_htlc_minimum_msat`],
+       /// [`ChannelDetails::balance_msat`], and [`ChannelDetails::outbound_capacity_msat`].
        pub next_outbound_htlc_limit_msat: u64,
+       /// The minimum value for sending a single HTLC to the remote peer. This is the equivalent of
+       /// [`ChannelDetails::next_outbound_htlc_limit_msat`] but represents a lower-bound, rather than
+       /// an upper-bound. This is intended for use when routing, allowing us to ensure we pick a
+       /// route which is valid.
+       pub next_outbound_htlc_minimum_msat: u64,
        /// The available inbound capacity for the remote peer to send HTLCs to us. This does not
        /// include any pending HTLCs which are not yet fully resolved (and, thus, whose balance is not
        /// available for inclusion in new inbound HTLCs).
@@ -1359,53 +1503,54 @@ impl ChannelDetails {
                self.short_channel_id.or(self.outbound_scid_alias)
        }
 
-       fn from_channel<Signer: WriteableEcdsaChannelSigner>(channel: &Channel<Signer>,
+       fn from_channel_context<Signer: WriteableEcdsaChannelSigner>(context: &ChannelContext<Signer>,
                best_block_height: u32, latest_features: InitFeatures) -> Self {
 
-               let balance = channel.get_available_balances();
+               let balance = context.get_available_balances();
                let (to_remote_reserve_satoshis, to_self_reserve_satoshis) =
-                       channel.get_holder_counterparty_selected_channel_reserve_satoshis();
+                       context.get_holder_counterparty_selected_channel_reserve_satoshis();
                ChannelDetails {
-                       channel_id: channel.channel_id(),
+                       channel_id: context.channel_id(),
                        counterparty: ChannelCounterparty {
-                               node_id: channel.get_counterparty_node_id(),
+                               node_id: context.get_counterparty_node_id(),
                                features: latest_features,
                                unspendable_punishment_reserve: to_remote_reserve_satoshis,
-                               forwarding_info: channel.counterparty_forwarding_info(),
+                               forwarding_info: context.counterparty_forwarding_info(),
                                // Ensures that we have actually received the `htlc_minimum_msat` value
                                // from the counterparty through the `OpenChannel` or `AcceptChannel`
                                // message (as they are always the first message from the counterparty).
                                // Else `Channel::get_counterparty_htlc_minimum_msat` could return the
                                // default `0` value set by `Channel::new_outbound`.
-                               outbound_htlc_minimum_msat: if channel.have_received_message() {
-                                       Some(channel.get_counterparty_htlc_minimum_msat()) } else { None },
-                               outbound_htlc_maximum_msat: channel.get_counterparty_htlc_maximum_msat(),
+                               outbound_htlc_minimum_msat: if context.have_received_message() {
+                                       Some(context.get_counterparty_htlc_minimum_msat()) } else { None },
+                               outbound_htlc_maximum_msat: context.get_counterparty_htlc_maximum_msat(),
                        },
-                       funding_txo: channel.get_funding_txo(),
+                       funding_txo: context.get_funding_txo(),
                        // Note that accept_channel (or open_channel) is always the first message, so
                        // `have_received_message` indicates that type negotiation has completed.
-                       channel_type: if channel.have_received_message() { Some(channel.get_channel_type().clone()) } else { None },
-                       short_channel_id: channel.get_short_channel_id(),
-                       outbound_scid_alias: if channel.is_usable() { Some(channel.outbound_scid_alias()) } else { None },
-                       inbound_scid_alias: channel.latest_inbound_scid_alias(),
-                       channel_value_satoshis: channel.get_value_satoshis(),
-                       feerate_sat_per_1000_weight: Some(channel.get_feerate_sat_per_1000_weight()),
+                       channel_type: if context.have_received_message() { Some(context.get_channel_type().clone()) } else { None },
+                       short_channel_id: context.get_short_channel_id(),
+                       outbound_scid_alias: if context.is_usable() { Some(context.outbound_scid_alias()) } else { None },
+                       inbound_scid_alias: context.latest_inbound_scid_alias(),
+                       channel_value_satoshis: context.get_value_satoshis(),
+                       feerate_sat_per_1000_weight: Some(context.get_feerate_sat_per_1000_weight()),
                        unspendable_punishment_reserve: to_self_reserve_satoshis,
                        balance_msat: balance.balance_msat,
                        inbound_capacity_msat: balance.inbound_capacity_msat,
                        outbound_capacity_msat: balance.outbound_capacity_msat,
                        next_outbound_htlc_limit_msat: balance.next_outbound_htlc_limit_msat,
-                       user_channel_id: channel.get_user_id(),
-                       confirmations_required: channel.minimum_depth(),
-                       confirmations: Some(channel.get_funding_tx_confirmations(best_block_height)),
-                       force_close_spend_delay: channel.get_counterparty_selected_contest_delay(),
-                       is_outbound: channel.is_outbound(),
-                       is_channel_ready: channel.is_usable(),
-                       is_usable: channel.is_live(),
-                       is_public: channel.should_announce(),
-                       inbound_htlc_minimum_msat: Some(channel.get_holder_htlc_minimum_msat()),
-                       inbound_htlc_maximum_msat: channel.get_holder_htlc_maximum_msat(),
-                       config: Some(channel.config()),
+                       next_outbound_htlc_minimum_msat: balance.next_outbound_htlc_minimum_msat,
+                       user_channel_id: context.get_user_id(),
+                       confirmations_required: context.minimum_depth(),
+                       confirmations: Some(context.get_funding_tx_confirmations(best_block_height)),
+                       force_close_spend_delay: context.get_counterparty_selected_contest_delay(),
+                       is_outbound: context.is_outbound(),
+                       is_channel_ready: context.is_usable(),
+                       is_usable: context.is_live(),
+                       is_public: context.should_announce(),
+                       inbound_htlc_minimum_msat: Some(context.get_holder_htlc_minimum_msat()),
+                       inbound_htlc_maximum_msat: context.get_holder_htlc_maximum_msat(),
+                       config: Some(context.config()),
                }
        }
 }
@@ -1502,14 +1647,23 @@ macro_rules! handle_error {
                                Err(err)
                        },
                }
-       } }
+       } };
+       ($self: ident, $internal: expr) => {
+               match $internal {
+                       Ok(res) => Ok(res),
+                       Err((chan, msg_handle_err)) => {
+                               let counterparty_node_id = chan.get_counterparty_node_id();
+                               handle_error!($self, Err(msg_handle_err), counterparty_node_id).map_err(|err| (chan, err))
+                       },
+               }
+       };
 }
 
 macro_rules! update_maps_on_chan_removal {
-       ($self: expr, $channel: expr) => {{
-               $self.id_to_peer.lock().unwrap().remove(&$channel.channel_id());
+       ($self: expr, $channel_context: expr) => {{
+               $self.id_to_peer.lock().unwrap().remove(&$channel_context.channel_id());
                let mut short_to_chan_info = $self.short_to_chan_info.write().unwrap();
-               if let Some(short_id) = $channel.get_short_channel_id() {
+               if let Some(short_id) = $channel_context.get_short_channel_id() {
                        short_to_chan_info.remove(&short_id);
                } else {
                        // If the channel was never confirmed on-chain prior to its closure, remove the
@@ -1518,10 +1672,10 @@ macro_rules! update_maps_on_chan_removal {
                        // also don't want a counterparty to be able to trivially cause a memory leak by simply
                        // opening a million channels with us which are closed before we ever reach the funding
                        // stage.
-                       let alias_removed = $self.outbound_scid_aliases.lock().unwrap().remove(&$channel.outbound_scid_alias());
+                       let alias_removed = $self.outbound_scid_aliases.lock().unwrap().remove(&$channel_context.outbound_scid_alias());
                        debug_assert!(alias_removed);
                }
-               short_to_chan_info.remove(&$channel.outbound_scid_alias());
+               short_to_chan_info.remove(&$channel_context.outbound_scid_alias());
        }}
 }
 
@@ -1537,12 +1691,25 @@ macro_rules! convert_chan_err {
                        },
                        ChannelError::Close(msg) => {
                                log_error!($self.logger, "Closing channel {} due to close-required error: {}", log_bytes!($channel_id[..]), msg);
-                               update_maps_on_chan_removal!($self, $channel);
-                               let shutdown_res = $channel.force_shutdown(true);
-                               (true, MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, $channel.get_user_id(),
+                               update_maps_on_chan_removal!($self, &$channel.context);
+                               let shutdown_res = $channel.context.force_shutdown(true);
+                               (true, MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, $channel.context.get_user_id(),
                                        shutdown_res, $self.get_channel_update_for_broadcast(&$channel).ok()))
                        },
                }
+       };
+       ($self: ident, $err: expr, $channel_context: expr, $channel_id: expr, PREFUNDED) => {
+               match $err {
+                       // We should only ever have `ChannelError::Close` when prefunded channels error.
+                       // In any case, just close the channel.
+                       ChannelError::Warn(msg) | ChannelError::Ignore(msg) | ChannelError::Close(msg) => {
+                               log_error!($self.logger, "Closing prefunded channel {} due to an error: {}", log_bytes!($channel_id[..]), msg);
+                               update_maps_on_chan_removal!($self, &$channel_context);
+                               let shutdown_res = $channel_context.force_shutdown(false);
+                               (true, MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, $channel_context.get_user_id(),
+                                       shutdown_res, None))
+                       },
+               }
        }
 }
 
@@ -1561,6 +1728,21 @@ macro_rules! break_chan_entry {
        }
 }
 
+macro_rules! try_v1_outbound_chan_entry {
+       ($self: ident, $res: expr, $entry: expr) => {
+               match $res {
+                       Ok(res) => res,
+                       Err(e) => {
+                               let (drop, res) = convert_chan_err!($self, e, $entry.get_mut().context, $entry.key(), PREFUNDED);
+                               if drop {
+                                       $entry.remove_entry();
+                               }
+                               return Err(res);
+                       }
+               }
+       }
+}
+
 macro_rules! try_chan_entry {
        ($self: ident, $res: expr, $entry: expr) => {
                match $res {
@@ -1580,7 +1762,7 @@ macro_rules! remove_channel {
        ($self: expr, $entry: expr) => {
                {
                        let channel = $entry.remove_entry().1;
-                       update_maps_on_chan_removal!($self, channel);
+                       update_maps_on_chan_removal!($self, &channel.context);
                        channel
                }
        }
@@ -1589,18 +1771,18 @@ macro_rules! remove_channel {
 macro_rules! send_channel_ready {
        ($self: ident, $pending_msg_events: expr, $channel: expr, $channel_ready_msg: expr) => {{
                $pending_msg_events.push(events::MessageSendEvent::SendChannelReady {
-                       node_id: $channel.get_counterparty_node_id(),
+                       node_id: $channel.context.get_counterparty_node_id(),
                        msg: $channel_ready_msg,
                });
                // Note that we may send a `channel_ready` multiple times for a channel if we reconnect, so
                // we allow collisions, but we shouldn't ever be updating the channel ID pointed to.
                let mut short_to_chan_info = $self.short_to_chan_info.write().unwrap();
-               let outbound_alias_insert = short_to_chan_info.insert($channel.outbound_scid_alias(), ($channel.get_counterparty_node_id(), $channel.channel_id()));
-               assert!(outbound_alias_insert.is_none() || outbound_alias_insert.unwrap() == ($channel.get_counterparty_node_id(), $channel.channel_id()),
+               let outbound_alias_insert = short_to_chan_info.insert($channel.context.outbound_scid_alias(), ($channel.context.get_counterparty_node_id(), $channel.context.channel_id()));
+               assert!(outbound_alias_insert.is_none() || outbound_alias_insert.unwrap() == ($channel.context.get_counterparty_node_id(), $channel.context.channel_id()),
                        "SCIDs should never collide - ensure you weren't behind the chain tip by a full month when creating channels");
-               if let Some(real_scid) = $channel.get_short_channel_id() {
-                       let scid_insert = short_to_chan_info.insert(real_scid, ($channel.get_counterparty_node_id(), $channel.channel_id()));
-                       assert!(scid_insert.is_none() || scid_insert.unwrap() == ($channel.get_counterparty_node_id(), $channel.channel_id()),
+               if let Some(real_scid) = $channel.context.get_short_channel_id() {
+                       let scid_insert = short_to_chan_info.insert(real_scid, ($channel.context.get_counterparty_node_id(), $channel.context.channel_id()));
+                       assert!(scid_insert.is_none() || scid_insert.unwrap() == ($channel.context.get_counterparty_node_id(), $channel.context.channel_id()),
                                "SCIDs should never collide - ensure you weren't behind the chain tip by a full month when creating channels");
                }
        }}
@@ -1608,41 +1790,41 @@ macro_rules! send_channel_ready {
 
 macro_rules! emit_channel_pending_event {
        ($locked_events: expr, $channel: expr) => {
-               if $channel.should_emit_channel_pending_event() {
+               if $channel.context.should_emit_channel_pending_event() {
                        $locked_events.push_back((events::Event::ChannelPending {
-                               channel_id: $channel.channel_id(),
-                               former_temporary_channel_id: $channel.temporary_channel_id(),
-                               counterparty_node_id: $channel.get_counterparty_node_id(),
-                               user_channel_id: $channel.get_user_id(),
-                               funding_txo: $channel.get_funding_txo().unwrap().into_bitcoin_outpoint(),
+                               channel_id: $channel.context.channel_id(),
+                               former_temporary_channel_id: $channel.context.temporary_channel_id(),
+                               counterparty_node_id: $channel.context.get_counterparty_node_id(),
+                               user_channel_id: $channel.context.get_user_id(),
+                               funding_txo: $channel.context.get_funding_txo().unwrap().into_bitcoin_outpoint(),
                        }, None));
-                       $channel.set_channel_pending_event_emitted();
+                       $channel.context.set_channel_pending_event_emitted();
                }
        }
 }
 
 macro_rules! emit_channel_ready_event {
        ($locked_events: expr, $channel: expr) => {
-               if $channel.should_emit_channel_ready_event() {
-                       debug_assert!($channel.channel_pending_event_emitted());
+               if $channel.context.should_emit_channel_ready_event() {
+                       debug_assert!($channel.context.channel_pending_event_emitted());
                        $locked_events.push_back((events::Event::ChannelReady {
-                               channel_id: $channel.channel_id(),
-                               user_channel_id: $channel.get_user_id(),
-                               counterparty_node_id: $channel.get_counterparty_node_id(),
-                               channel_type: $channel.get_channel_type().clone(),
+                               channel_id: $channel.context.channel_id(),
+                               user_channel_id: $channel.context.get_user_id(),
+                               counterparty_node_id: $channel.context.get_counterparty_node_id(),
+                               channel_type: $channel.context.get_channel_type().clone(),
                        }, None));
-                       $channel.set_channel_ready_event_emitted();
+                       $channel.context.set_channel_ready_event_emitted();
                }
        }
 }
 
 macro_rules! handle_monitor_update_completion {
-       ($self: ident, $update_id: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan: expr) => { {
+       ($self: ident, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan: expr) => { {
                let mut updates = $chan.monitor_updating_restored(&$self.logger,
                        &$self.node_signer, $self.genesis_hash, &$self.default_configuration,
                        $self.best_block.read().unwrap().height());
-               let counterparty_node_id = $chan.get_counterparty_node_id();
-               let channel_update = if updates.channel_ready.is_some() && $chan.is_usable() {
+               let counterparty_node_id = $chan.context.get_counterparty_node_id();
+               let channel_update = if updates.channel_ready.is_some() && $chan.context.is_usable() {
                        // We only send a channel_update in the case where we are just now sending a
                        // channel_ready and the channel is in a usable state. We may re-send a
                        // channel_update later through the announcement_signatures process for public
@@ -1657,7 +1839,7 @@ macro_rules! handle_monitor_update_completion {
                } else { None };
 
                let update_actions = $peer_state.monitor_update_blocked_actions
-                       .remove(&$chan.channel_id()).unwrap_or(Vec::new());
+                       .remove(&$chan.context.channel_id()).unwrap_or(Vec::new());
 
                let htlc_forwards = $self.handle_channel_resumption(
                        &mut $peer_state.pending_msg_events, $chan, updates.raa,
@@ -1668,7 +1850,7 @@ macro_rules! handle_monitor_update_completion {
                        $peer_state.pending_msg_events.push(upd);
                }
 
-               let channel_id = $chan.channel_id();
+               let channel_id = $chan.context.channel_id();
                core::mem::drop($peer_state_lock);
                core::mem::drop($per_peer_state_lock);
 
@@ -1686,38 +1868,67 @@ macro_rules! handle_monitor_update_completion {
 }
 
 macro_rules! handle_new_monitor_update {
-       ($self: ident, $update_res: expr, $update_id: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan: expr, MANUALLY_REMOVING, $remove: expr) => { {
+       ($self: ident, $update_res: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan: expr, _internal, $remove: expr, $completed: expr) => { {
                // update_maps_on_chan_removal needs to be able to take id_to_peer, so make sure we can in
                // any case so that it won't deadlock.
                debug_assert_ne!($self.id_to_peer.held_by_thread(), LockHeldState::HeldByThread);
+               #[cfg(debug_assertions)] {
+                       debug_assert!($self.background_events_processed_since_startup.load(Ordering::Acquire));
+               }
                match $update_res {
                        ChannelMonitorUpdateStatus::InProgress => {
                                log_debug!($self.logger, "ChannelMonitor update for {} in flight, holding messages until the update completes.",
-                                       log_bytes!($chan.channel_id()[..]));
-                               Ok(())
+                                       log_bytes!($chan.context.channel_id()[..]));
+                               Ok(false)
                        },
                        ChannelMonitorUpdateStatus::PermanentFailure => {
                                log_error!($self.logger, "Closing channel {} due to monitor update ChannelMonitorUpdateStatus::PermanentFailure",
-                                       log_bytes!($chan.channel_id()[..]));
-                               update_maps_on_chan_removal!($self, $chan);
-                               let res: Result<(), _> = Err(MsgHandleErrInternal::from_finish_shutdown(
-                                       "ChannelMonitor storage failure".to_owned(), $chan.channel_id(),
-                                       $chan.get_user_id(), $chan.force_shutdown(false),
+                                       log_bytes!($chan.context.channel_id()[..]));
+                               update_maps_on_chan_removal!($self, &$chan.context);
+                               let res = Err(MsgHandleErrInternal::from_finish_shutdown(
+                                       "ChannelMonitor storage failure".to_owned(), $chan.context.channel_id(),
+                                       $chan.context.get_user_id(), $chan.context.force_shutdown(false),
                                        $self.get_channel_update_for_broadcast(&$chan).ok()));
                                $remove;
                                res
                        },
                        ChannelMonitorUpdateStatus::Completed => {
-                               $chan.complete_one_mon_update($update_id);
-                               if $chan.no_monitor_updates_pending() {
-                                       handle_monitor_update_completion!($self, $update_id, $peer_state_lock, $peer_state, $per_peer_state_lock, $chan);
-                               }
-                               Ok(())
+                               $completed;
+                               Ok(true)
                        },
                }
        } };
-       ($self: ident, $update_res: expr, $update_id: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan_entry: expr) => {
-               handle_new_monitor_update!($self, $update_res, $update_id, $peer_state_lock, $peer_state, $per_peer_state_lock, $chan_entry.get_mut(), MANUALLY_REMOVING, $chan_entry.remove_entry())
+       ($self: ident, $update_res: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan: expr, MANUALLY_REMOVING_INITIAL_MONITOR, $remove: expr) => {
+               handle_new_monitor_update!($self, $update_res, $peer_state_lock, $peer_state,
+                       $per_peer_state_lock, $chan, _internal, $remove,
+                       handle_monitor_update_completion!($self, $peer_state_lock, $peer_state, $per_peer_state_lock, $chan))
+       };
+       ($self: ident, $update_res: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan_entry: expr, INITIAL_MONITOR) => {
+               handle_new_monitor_update!($self, $update_res, $peer_state_lock, $peer_state, $per_peer_state_lock, $chan_entry.get_mut(), MANUALLY_REMOVING_INITIAL_MONITOR, $chan_entry.remove_entry())
+       };
+       ($self: ident, $funding_txo: expr, $update: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan: expr, MANUALLY_REMOVING, $remove: expr) => { {
+               let in_flight_updates = $peer_state.in_flight_monitor_updates.entry($funding_txo)
+                       .or_insert_with(Vec::new);
+               // During startup, we push monitor updates as background events through to here in
+               // order to replay updates that were in-flight when we shut down. Thus, we have to
+               // filter for uniqueness here.
+               let idx = in_flight_updates.iter().position(|upd| upd == &$update)
+                       .unwrap_or_else(|| {
+                               in_flight_updates.push($update);
+                               in_flight_updates.len() - 1
+                       });
+               let update_res = $self.chain_monitor.update_channel($funding_txo, &in_flight_updates[idx]);
+               handle_new_monitor_update!($self, update_res, $peer_state_lock, $peer_state,
+                       $per_peer_state_lock, $chan, _internal, $remove,
+                       {
+                               let _ = in_flight_updates.remove(idx);
+                               if in_flight_updates.is_empty() && $chan.blocked_monitor_updates_pending() == 0 {
+                                       handle_monitor_update_completion!($self, $peer_state_lock, $peer_state, $per_peer_state_lock, $chan);
+                               }
+                       })
+       } };
+       ($self: ident, $funding_txo: expr, $update: expr, $peer_state_lock: expr, $peer_state: expr, $per_peer_state_lock: expr, $chan_entry: expr) => {
+               handle_new_monitor_update!($self, $funding_txo, $update, $peer_state_lock, $peer_state, $per_peer_state_lock, $chan_entry.get_mut(), MANUALLY_REMOVING, $chan_entry.remove_entry())
        }
 }
 
@@ -1736,6 +1947,10 @@ macro_rules! process_events_body {
                                // persists happen while processing monitor events.
                                let _read_guard = $self.total_consistency_lock.read().unwrap();
 
+                               // Because `handle_post_event_actions` may send `ChannelMonitorUpdate`s to the user we must
+                               // ensure any startup-generated background events are handled first.
+                               if $self.process_background_events() == NotifyOption::DoPersist { result = NotifyOption::DoPersist; }
+
                                // TODO: This behavior should be documented. It's unintuitive that we query
                                // ChannelMonitors when clearing other events.
                                if $self.process_pending_monitor_events() {
@@ -1845,6 +2060,8 @@ where
                        pending_events_processor: AtomicBool::new(false),
                        pending_background_events: Mutex::new(Vec::new()),
                        total_consistency_lock: RwLock::new(()),
+                       #[cfg(debug_assertions)]
+                       background_events_processed_since_startup: AtomicBool::new(false),
                        persistence_notifier: Notifier::new(),
 
                        entropy_source,
@@ -1913,7 +2130,7 @@ where
                        return Err(APIError::APIMisuseError { err: format!("Channel value must be at least 1000 satoshis. It was {}", channel_value_satoshis) });
                }
 
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                // We want to make sure the lock is actually acquired by PersistenceNotifierGuard.
                debug_assert!(&self.total_consistency_lock.try_write().is_err());
 
@@ -1927,7 +2144,7 @@ where
                        let outbound_scid_alias = self.create_and_insert_outbound_scid_alias();
                        let their_features = &peer_state.latest_features;
                        let config = if override_config.is_some() { override_config.as_ref().unwrap() } else { &self.default_configuration };
-                       match Channel::new_outbound(&self.fee_estimator, &self.entropy_source, &self.signer_provider, their_network_key,
+                       match OutboundV1Channel::new(&self.fee_estimator, &self.entropy_source, &self.signer_provider, their_network_key,
                                their_features, channel_value_satoshis, push_msat, user_channel_id, config,
                                self.best_block.read().unwrap().height(), outbound_scid_alias)
                        {
@@ -1940,8 +2157,8 @@ where
                };
                let res = channel.get_open_channel(self.genesis_hash.clone());
 
-               let temporary_channel_id = channel.channel_id();
-               match peer_state.channel_by_id.entry(temporary_channel_id) {
+               let temporary_channel_id = channel.context.channel_id();
+               match peer_state.outbound_v1_channel_by_id.entry(temporary_channel_id) {
                        hash_map::Entry::Occupied(_) => {
                                if cfg!(fuzzing) {
                                        return Err(APIError::APIMisuseError { err: "Fuzzy bad RNG".to_owned() });
@@ -1959,7 +2176,7 @@ where
                Ok(temporary_channel_id)
        }
 
-       fn list_channels_with_filter<Fn: FnMut(&(&[u8; 32], &Channel<<SP::Target as SignerProvider>::Signer>)) -> bool + Copy>(&self, f: Fn) -> Vec<ChannelDetails> {
+       fn list_funded_channels_with_filter<Fn: FnMut(&(&[u8; 32], &Channel<<SP::Target as SignerProvider>::Signer>)) -> bool + Copy>(&self, f: Fn) -> Vec<ChannelDetails> {
                // Allocate our best estimate of the number of channels we have in the `res`
                // Vec. Sadly the `short_to_chan_info` map doesn't cover channels without
                // a scid or a scid alias, and the `id_to_peer` shouldn't be used outside
@@ -1974,7 +2191,7 @@ where
                                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                                let peer_state = &mut *peer_state_lock;
                                for (_channel_id, channel) in peer_state.channel_by_id.iter().filter(f) {
-                                       let details = ChannelDetails::from_channel(channel, best_block_height,
+                                       let details = ChannelDetails::from_channel_context(&channel.context, best_block_height,
                                                peer_state.latest_features.clone());
                                        res.push(details);
                                }
@@ -1986,7 +2203,37 @@ where
        /// Gets the list of open channels, in random order. See [`ChannelDetails`] field documentation for
        /// more information.
        pub fn list_channels(&self) -> Vec<ChannelDetails> {
-               self.list_channels_with_filter(|_| true)
+               // Allocate our best estimate of the number of channels we have in the `res`
+               // Vec. Sadly the `short_to_chan_info` map doesn't cover channels without
+               // a scid or a scid alias, and the `id_to_peer` shouldn't be used outside
+               // of the ChannelMonitor handling. Therefore reallocations may still occur, but is
+               // unlikely as the `short_to_chan_info` map often contains 2 entries for
+               // the same channel.
+               let mut res = Vec::with_capacity(self.short_to_chan_info.read().unwrap().len());
+               {
+                       let best_block_height = self.best_block.read().unwrap().height();
+                       let per_peer_state = self.per_peer_state.read().unwrap();
+                       for (_cp_id, peer_state_mutex) in per_peer_state.iter() {
+                               let mut peer_state_lock = peer_state_mutex.lock().unwrap();
+                               let peer_state = &mut *peer_state_lock;
+                               for (_channel_id, channel) in peer_state.channel_by_id.iter() {
+                                       let details = ChannelDetails::from_channel_context(&channel.context, best_block_height,
+                                               peer_state.latest_features.clone());
+                                       res.push(details);
+                               }
+                               for (_channel_id, channel) in peer_state.inbound_v1_channel_by_id.iter() {
+                                       let details = ChannelDetails::from_channel_context(&channel.context, best_block_height,
+                                               peer_state.latest_features.clone());
+                                       res.push(details);
+                               }
+                               for (_channel_id, channel) in peer_state.outbound_v1_channel_by_id.iter() {
+                                       let details = ChannelDetails::from_channel_context(&channel.context, best_block_height,
+                                               peer_state.latest_features.clone());
+                                       res.push(details);
+                               }
+                       }
+               }
+               res
        }
 
        /// Gets the list of usable channels, in random order. Useful as an argument to
@@ -1999,7 +2246,7 @@ where
                // Note we use is_live here instead of usable which leads to somewhat confused
                // internal/external nomenclature, but that's ok cause that's probably what the user
                // really wanted anyway.
-               self.list_channels_with_filter(|&(_, ref channel)| channel.is_live())
+               self.list_funded_channels_with_filter(|&(_, ref channel)| channel.context.is_live())
        }
 
        /// Gets the list of channels we have with a given counterparty, in random order.
@@ -2014,7 +2261,7 @@ where
                        return peer_state.channel_by_id
                                .iter()
                                .map(|(_, channel)|
-                                       ChannelDetails::from_channel(channel, best_block_height, features.clone()))
+                                       ChannelDetails::from_channel_context(&channel.context, best_block_height, features.clone()))
                                .collect();
                }
                vec![]
@@ -2049,25 +2296,25 @@ where
        }
 
        /// Helper function that issues the channel close events
-       fn issue_channel_close_events(&self, channel: &Channel<<SP::Target as SignerProvider>::Signer>, closure_reason: ClosureReason) {
+       fn issue_channel_close_events(&self, context: &ChannelContext<<SP::Target as SignerProvider>::Signer>, closure_reason: ClosureReason) {
                let mut pending_events_lock = self.pending_events.lock().unwrap();
-               match channel.unbroadcasted_funding() {
+               match context.unbroadcasted_funding() {
                        Some(transaction) => {
                                pending_events_lock.push_back((events::Event::DiscardFunding {
-                                       channel_id: channel.channel_id(), transaction
+                                       channel_id: context.channel_id(), transaction
                                }, None));
                        },
                        None => {},
                }
                pending_events_lock.push_back((events::Event::ChannelClosed {
-                       channel_id: channel.channel_id(),
-                       user_channel_id: channel.get_user_id(),
+                       channel_id: context.channel_id(),
+                       user_channel_id: context.get_user_id(),
                        reason: closure_reason
                }, None));
        }
 
        fn close_channel_internal(&self, channel_id: &[u8; 32], counterparty_node_id: &PublicKey, target_feerate_sats_per_1000_weight: Option<u32>, override_shutdown_script: Option<ShutdownScript>) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let mut failed_htlcs: Vec<(HTLCSource, PaymentHash)>;
                let result: Result<(), _> = loop {
@@ -2080,7 +2327,7 @@ where
                        let peer_state = &mut *peer_state_lock;
                        match peer_state.channel_by_id.entry(channel_id.clone()) {
                                hash_map::Entry::Occupied(mut chan_entry) => {
-                                       let funding_txo_opt = chan_entry.get().get_funding_txo();
+                                       let funding_txo_opt = chan_entry.get().context.get_funding_txo();
                                        let their_features = &peer_state.latest_features;
                                        let (shutdown_msg, mut monitor_update_opt, htlcs) = chan_entry.get_mut()
                                                .get_shutdown(&self.signer_provider, their_features, target_feerate_sats_per_1000_weight, override_shutdown_script)?;
@@ -2096,9 +2343,8 @@ where
 
                                        // Update the monitor with the shutdown script if necessary.
                                        if let Some(monitor_update) = monitor_update_opt.take() {
-                                               let update_id = monitor_update.update_id;
-                                               let update_res = self.chain_monitor.update_channel(funding_txo_opt.unwrap(), monitor_update);
-                                               break handle_new_monitor_update!(self, update_res, update_id, peer_state_lock, peer_state, per_peer_state, chan_entry);
+                                               break handle_new_monitor_update!(self, funding_txo_opt.unwrap(), monitor_update,
+                                                       peer_state_lock, peer_state, per_peer_state, chan_entry).map(|_| ());
                                        }
 
                                        if chan_entry.get().is_shutdown() {
@@ -2108,7 +2354,7 @@ where
                                                                msg: channel_update
                                                        });
                                                }
-                                               self.issue_channel_close_events(&channel, ClosureReason::HolderForceClosed);
+                                               self.issue_channel_close_events(&channel.context, ClosureReason::HolderForceClosed);
                                        }
                                        break Ok(());
                                },
@@ -2197,7 +2443,7 @@ where
                        let receiver = HTLCDestination::NextHopChannel { node_id: Some(counterparty_node_id), channel_id };
                        self.fail_htlc_backwards_internal(&source, &payment_hash, &reason, receiver);
                }
-               if let Some((funding_txo, monitor_update)) = monitor_update_option {
+               if let Some((_, funding_txo, monitor_update)) = monitor_update_option {
                        // There isn't anything we can do if we get an update failure - we're already
                        // force-closing. The monitor update on the required in-memory copy should broadcast
                        // the latest local state, which is the best we can do anyway. Thus, it is safe to
@@ -2213,34 +2459,50 @@ where
                let per_peer_state = self.per_peer_state.read().unwrap();
                let peer_state_mutex = per_peer_state.get(peer_node_id)
                        .ok_or_else(|| APIError::ChannelUnavailable { err: format!("Can't find a peer matching the passed counterparty node_id {}", peer_node_id) })?;
-               let mut chan = {
+               let (update_opt, counterparty_node_id) = {
                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                        let peer_state = &mut *peer_state_lock;
+                       let closure_reason = if let Some(peer_msg) = peer_msg {
+                               ClosureReason::CounterpartyForceClosed { peer_msg: UntrustedString(peer_msg.to_string()) }
+                       } else {
+                               ClosureReason::HolderForceClosed
+                       };
                        if let hash_map::Entry::Occupied(chan) = peer_state.channel_by_id.entry(channel_id.clone()) {
-                               if let Some(peer_msg) = peer_msg {
-                                       self.issue_channel_close_events(chan.get(),ClosureReason::CounterpartyForceClosed { peer_msg: UntrustedString(peer_msg.to_string()) });
-                               } else {
-                                       self.issue_channel_close_events(chan.get(),ClosureReason::HolderForceClosed);
-                               }
-                               remove_channel!(self, chan)
+                               log_error!(self.logger, "Force-closing channel {}", log_bytes!(channel_id[..]));
+                               self.issue_channel_close_events(&chan.get().context, closure_reason);
+                               let mut chan = remove_channel!(self, chan);
+                               self.finish_force_close_channel(chan.context.force_shutdown(broadcast));
+                               (self.get_channel_update_for_broadcast(&chan).ok(), chan.context.get_counterparty_node_id())
+                       } else if let hash_map::Entry::Occupied(chan) = peer_state.outbound_v1_channel_by_id.entry(channel_id.clone()) {
+                               log_error!(self.logger, "Force-closing channel {}", log_bytes!(channel_id[..]));
+                               self.issue_channel_close_events(&chan.get().context, closure_reason);
+                               let mut chan = remove_channel!(self, chan);
+                               self.finish_force_close_channel(chan.context.force_shutdown(false));
+                               // Prefunded channel has no update
+                               (None, chan.context.get_counterparty_node_id())
+                       } else if let hash_map::Entry::Occupied(chan) = peer_state.inbound_v1_channel_by_id.entry(channel_id.clone()) {
+                               log_error!(self.logger, "Force-closing channel {}", log_bytes!(channel_id[..]));
+                               self.issue_channel_close_events(&chan.get().context, closure_reason);
+                               let mut chan = remove_channel!(self, chan);
+                               self.finish_force_close_channel(chan.context.force_shutdown(false));
+                               // Prefunded channel has no update
+                               (None, chan.context.get_counterparty_node_id())
                        } else {
                                return Err(APIError::ChannelUnavailable{ err: format!("Channel with id {} not found for the passed counterparty node_id {}", log_bytes!(*channel_id), peer_node_id) });
                        }
                };
-               log_error!(self.logger, "Force-closing channel {}", log_bytes!(channel_id[..]));
-               self.finish_force_close_channel(chan.force_shutdown(broadcast));
-               if let Ok(update) = self.get_channel_update_for_broadcast(&chan) {
+               if let Some(update) = update_opt {
                        let mut peer_state = peer_state_mutex.lock().unwrap();
                        peer_state.pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                msg: update
                        });
                }
 
-               Ok(chan.get_counterparty_node_id())
+               Ok(counterparty_node_id)
        }
 
        fn force_close_sending_error(&self, channel_id: &[u8; 32], counterparty_node_id: &PublicKey, broadcast: bool) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                match self.force_close_channel_with_peer(channel_id, counterparty_node_id, None, broadcast) {
                        Ok(counterparty_node_id) => {
                                let per_peer_state = self.per_peer_state.read().unwrap();
@@ -2297,9 +2559,11 @@ where
                }
        }
 
-       fn construct_recv_pending_htlc_info(&self, hop_data: msgs::OnionHopData, shared_secret: [u8; 32],
-               payment_hash: PaymentHash, amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>) -> Result<PendingHTLCInfo, ReceiveError>
-       {
+       fn construct_recv_pending_htlc_info(
+               &self, hop_data: msgs::OnionHopData, shared_secret: [u8; 32], payment_hash: PaymentHash,
+               amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
+               counterparty_skimmed_fee_msat: Option<u64>,
+       ) -> Result<PendingHTLCInfo, ReceiveError> {
                // final_incorrect_cltv_expiry
                if hop_data.outgoing_cltv_value > cltv_expiry {
                        return Err(ReceiveError {
@@ -2325,7 +2589,10 @@ where
                                msg: "The final CLTV expiry is too soon to handle",
                        });
                }
-               if hop_data.amt_to_forward > amt_msat {
+               if (!allow_underpay && hop_data.amt_to_forward > amt_msat) ||
+                       (allow_underpay && hop_data.amt_to_forward >
+                        amt_msat.saturating_add(counterparty_skimmed_fee_msat.unwrap_or(0)))
+               {
                        return Err(ReceiveError {
                                err_code: 19,
                                err_data: amt_msat.to_be_bytes().to_vec(),
@@ -2342,20 +2609,7 @@ where
                                });
                        },
                        msgs::OnionHopDataFormat::FinalNode { payment_data, keysend_preimage, payment_metadata } => {
-                               if payment_data.is_some() && keysend_preimage.is_some() {
-                                       return Err(ReceiveError {
-                                               err_code: 0x4000|22,
-                                               err_data: Vec::new(),
-                                               msg: "We don't support MPP keysend payments",
-                                       });
-                               } else if let Some(data) = payment_data {
-                                       PendingHTLCRouting::Receive {
-                                               payment_data: data,
-                                               payment_metadata,
-                                               incoming_cltv_expiry: hop_data.outgoing_cltv_value,
-                                               phantom_shared_secret,
-                                       }
-                               } else if let Some(payment_preimage) = keysend_preimage {
+                               if let Some(payment_preimage) = keysend_preimage {
                                        // We need to check that the sender knows the keysend preimage before processing this
                                        // payment further. Otherwise, an intermediary routing hop forwarding non-keysend-HTLC X
                                        // could discover the final destination of X, by probing the adjacent nodes on the route
@@ -2369,12 +2623,26 @@ where
                                                        msg: "Payment preimage didn't match payment hash",
                                                });
                                        }
-
+                                       if !self.default_configuration.accept_mpp_keysend && payment_data.is_some() {
+                                               return Err(ReceiveError {
+                                                       err_code: 0x4000|22,
+                                                       err_data: Vec::new(),
+                                                       msg: "We don't support MPP keysend payments",
+                                               });
+                                       }
                                        PendingHTLCRouting::ReceiveKeysend {
+                                               payment_data,
                                                payment_preimage,
                                                payment_metadata,
                                                incoming_cltv_expiry: hop_data.outgoing_cltv_value,
                                        }
+                               } else if let Some(data) = payment_data {
+                                       PendingHTLCRouting::Receive {
+                                               payment_data: data,
+                                               payment_metadata,
+                                               incoming_cltv_expiry: hop_data.outgoing_cltv_value,
+                                               phantom_shared_secret,
+                                       }
                                } else {
                                        return Err(ReceiveError {
                                                err_code: 0x4000|0x2000|3,
@@ -2391,15 +2659,18 @@ where
                        incoming_amt_msat: Some(amt_msat),
                        outgoing_amt_msat: hop_data.amt_to_forward,
                        outgoing_cltv_value: hop_data.outgoing_cltv_value,
+                       skimmed_fee_msat: counterparty_skimmed_fee_msat,
                })
        }
 
-       fn decode_update_add_htlc_onion(&self, msg: &msgs::UpdateAddHTLC) -> PendingHTLCStatus {
+       fn decode_update_add_htlc_onion(
+               &self, msg: &msgs::UpdateAddHTLC
+       ) -> Result<(onion_utils::Hop, [u8; 32], Option<Result<PublicKey, secp256k1::Error>>), HTLCFailureMsg> {
                macro_rules! return_malformed_err {
                        ($msg: expr, $err_code: expr) => {
                                {
                                        log_info!(self.logger, "Failed to accept/forward incoming HTLC: {}", $msg);
-                                       return PendingHTLCStatus::Fail(HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC {
+                                       return Err(HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC {
                                                channel_id: msg.channel_id,
                                                htlc_id: msg.htlc_id,
                                                sha256_of_onion: Sha256::hash(&msg.onion_routing_packet.hop_data).into_inner(),
@@ -2430,7 +2701,7 @@ where
                        ($msg: expr, $err_code: expr, $data: expr) => {
                                {
                                        log_info!(self.logger, "Failed to accept/forward incoming HTLC: {}", $msg);
-                                       return PendingHTLCStatus::Fail(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
+                                       return Err(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
                                                channel_id: msg.channel_id,
                                                htlc_id: msg.htlc_id,
                                                reason: HTLCFailReason::reason($err_code, $data.to_vec())
@@ -2449,11 +2720,186 @@ where
                                return_err!(err_msg, err_code, &[0; 0]);
                        },
                };
+               let (outgoing_scid, outgoing_amt_msat, outgoing_cltv_value, next_packet_pk_opt) = match next_hop {
+                       onion_utils::Hop::Forward {
+                               next_hop_data: msgs::OnionHopData {
+                                       format: msgs::OnionHopDataFormat::NonFinalNode { short_channel_id }, amt_to_forward,
+                                       outgoing_cltv_value,
+                               }, ..
+                       } => {
+                               let next_pk = onion_utils::next_hop_packet_pubkey(&self.secp_ctx,
+                                       msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
+                               (short_channel_id, amt_to_forward, outgoing_cltv_value, Some(next_pk))
+                       },
+                       // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
+                       // inbound channel's state.
+                       onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
+                       onion_utils::Hop::Forward {
+                               next_hop_data: msgs::OnionHopData { format: msgs::OnionHopDataFormat::FinalNode { .. }, .. }, ..
+                       } => {
+                               return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
+                       }
+               };
 
-               let pending_forward_info = match next_hop {
+               // Perform outbound checks here instead of in [`Self::construct_pending_htlc_info`] because we
+               // can't hold the outbound peer state lock at the same time as the inbound peer state lock.
+               if let Some((err, mut code, chan_update)) = loop {
+                       let id_option = self.short_to_chan_info.read().unwrap().get(&outgoing_scid).cloned();
+                       let forwarding_chan_info_opt = match id_option {
+                               None => { // unknown_next_peer
+                                       // Note that this is likely a timing oracle for detecting whether an scid is a
+                                       // phantom or an intercept.
+                                       if (self.default_configuration.accept_intercept_htlcs &&
+                                               fake_scid::is_valid_intercept(&self.fake_scid_rand_bytes, outgoing_scid, &self.genesis_hash)) ||
+                                               fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, outgoing_scid, &self.genesis_hash)
+                                       {
+                                               None
+                                       } else {
+                                               break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
+                                       }
+                               },
+                               Some((cp_id, id)) => Some((cp_id.clone(), id.clone())),
+                       };
+                       let chan_update_opt = if let Some((counterparty_node_id, forwarding_id)) = forwarding_chan_info_opt {
+                               let per_peer_state = self.per_peer_state.read().unwrap();
+                               let peer_state_mutex_opt = per_peer_state.get(&counterparty_node_id);
+                               if peer_state_mutex_opt.is_none() {
+                                       break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
+                               }
+                               let mut peer_state_lock = peer_state_mutex_opt.unwrap().lock().unwrap();
+                               let peer_state = &mut *peer_state_lock;
+                               let chan = match peer_state.channel_by_id.get_mut(&forwarding_id) {
+                                       None => {
+                                               // Channel was removed. The short_to_chan_info and channel_by_id maps
+                                               // have no consistency guarantees.
+                                               break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
+                                       },
+                                       Some(chan) => chan
+                               };
+                               if !chan.context.should_announce() && !self.default_configuration.accept_forwards_to_priv_channels {
+                                       // Note that the behavior here should be identical to the above block - we
+                                       // should NOT reveal the existence or non-existence of a private channel if
+                                       // we don't allow forwards outbound over them.
+                                       break Some(("Refusing to forward to a private channel based on our config.", 0x4000 | 10, None));
+                               }
+                               if chan.context.get_channel_type().supports_scid_privacy() && outgoing_scid != chan.context.outbound_scid_alias() {
+                                       // `option_scid_alias` (referred to in LDK as `scid_privacy`) means
+                                       // "refuse to forward unless the SCID alias was used", so we pretend
+                                       // we don't have the channel here.
+                                       break Some(("Refusing to forward over real channel SCID as our counterparty requested.", 0x4000 | 10, None));
+                               }
+                               let chan_update_opt = self.get_channel_update_for_onion(outgoing_scid, chan).ok();
+
+                               // Note that we could technically not return an error yet here and just hope
+                               // that the connection is reestablished or monitor updated by the time we get
+                               // around to doing the actual forward, but better to fail early if we can and
+                               // hopefully an attacker trying to path-trace payments cannot make this occur
+                               // on a small/per-node/per-channel scale.
+                               if !chan.context.is_live() { // channel_disabled
+                                       // If the channel_update we're going to return is disabled (i.e. the
+                                       // peer has been disabled for some time), return `channel_disabled`,
+                                       // otherwise return `temporary_channel_failure`.
+                                       if chan_update_opt.as_ref().map(|u| u.contents.flags & 2 == 2).unwrap_or(false) {
+                                               break Some(("Forwarding channel has been disconnected for some time.", 0x1000 | 20, chan_update_opt));
+                                       } else {
+                                               break Some(("Forwarding channel is not in a ready state.", 0x1000 | 7, chan_update_opt));
+                                       }
+                               }
+                               if outgoing_amt_msat < chan.context.get_counterparty_htlc_minimum_msat() { // amount_below_minimum
+                                       break Some(("HTLC amount was below the htlc_minimum_msat", 0x1000 | 11, chan_update_opt));
+                               }
+                               if let Err((err, code)) = chan.htlc_satisfies_config(&msg, outgoing_amt_msat, outgoing_cltv_value) {
+                                       break Some((err, code, chan_update_opt));
+                               }
+                               chan_update_opt
+                       } else {
+                               if (msg.cltv_expiry as u64) < (outgoing_cltv_value) as u64 + MIN_CLTV_EXPIRY_DELTA as u64 {
+                                       // We really should set `incorrect_cltv_expiry` here but as we're not
+                                       // forwarding over a real channel we can't generate a channel_update
+                                       // for it. Instead we just return a generic temporary_node_failure.
+                                       break Some((
+                                                       "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
+                                                       0x2000 | 2, None,
+                                       ));
+                               }
+                               None
+                       };
+
+                       let cur_height = self.best_block.read().unwrap().height() + 1;
+                       // Theoretically, channel counterparty shouldn't send us a HTLC expiring now,
+                       // but we want to be robust wrt to counterparty packet sanitization (see
+                       // HTLC_FAIL_BACK_BUFFER rationale).
+                       if msg.cltv_expiry <= cur_height + HTLC_FAIL_BACK_BUFFER as u32 { // expiry_too_soon
+                               break Some(("CLTV expiry is too close", 0x1000 | 14, chan_update_opt));
+                       }
+                       if msg.cltv_expiry > cur_height + CLTV_FAR_FAR_AWAY as u32 { // expiry_too_far
+                               break Some(("CLTV expiry is too far in the future", 21, None));
+                       }
+                       // If the HTLC expires ~now, don't bother trying to forward it to our
+                       // counterparty. They should fail it anyway, but we don't want to bother with
+                       // the round-trips or risk them deciding they definitely want the HTLC and
+                       // force-closing to ensure they get it if we're offline.
+                       // We previously had a much more aggressive check here which tried to ensure
+                       // our counterparty receives an HTLC which has *our* risk threshold met on it,
+                       // but there is no need to do that, and since we're a bit conservative with our
+                       // risk threshold it just results in failing to forward payments.
+                       if (outgoing_cltv_value) as u64 <= (cur_height + LATENCY_GRACE_PERIOD_BLOCKS) as u64 {
+                               break Some(("Outgoing CLTV value is too soon", 0x1000 | 14, chan_update_opt));
+                       }
+
+                       break None;
+               }
+               {
+                       let mut res = VecWriter(Vec::with_capacity(chan_update.serialized_length() + 2 + 8 + 2));
+                       if let Some(chan_update) = chan_update {
+                               if code == 0x1000 | 11 || code == 0x1000 | 12 {
+                                       msg.amount_msat.write(&mut res).expect("Writes cannot fail");
+                               }
+                               else if code == 0x1000 | 13 {
+                                       msg.cltv_expiry.write(&mut res).expect("Writes cannot fail");
+                               }
+                               else if code == 0x1000 | 20 {
+                                       // TODO: underspecified, follow https://github.com/lightning/bolts/issues/791
+                                       0u16.write(&mut res).expect("Writes cannot fail");
+                               }
+                               (chan_update.serialized_length() as u16 + 2).write(&mut res).expect("Writes cannot fail");
+                               msgs::ChannelUpdate::TYPE.write(&mut res).expect("Writes cannot fail");
+                               chan_update.write(&mut res).expect("Writes cannot fail");
+                       } else if code & 0x1000 == 0x1000 {
+                               // If we're trying to return an error that requires a `channel_update` but
+                               // we're forwarding to a phantom or intercept "channel" (i.e. cannot
+                               // generate an update), just use the generic "temporary_node_failure"
+                               // instead.
+                               code = 0x2000 | 2;
+                       }
+                       return_err!(err, code, &res.0[..]);
+               }
+               Ok((next_hop, shared_secret, next_packet_pk_opt))
+       }
+
+       fn construct_pending_htlc_status<'a>(
+               &self, msg: &msgs::UpdateAddHTLC, shared_secret: [u8; 32], decoded_hop: onion_utils::Hop,
+               allow_underpay: bool, next_packet_pubkey_opt: Option<Result<PublicKey, secp256k1::Error>>
+       ) -> PendingHTLCStatus {
+               macro_rules! return_err {
+                       ($msg: expr, $err_code: expr, $data: expr) => {
+                               {
+                                       log_info!(self.logger, "Failed to accept/forward incoming HTLC: {}", $msg);
+                                       return PendingHTLCStatus::Fail(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
+                                               channel_id: msg.channel_id,
+                                               htlc_id: msg.htlc_id,
+                                               reason: HTLCFailReason::reason($err_code, $data.to_vec())
+                                                       .get_encrypted_failure_packet(&shared_secret, &None),
+                                       }));
+                               }
+                       }
+               }
+               match decoded_hop {
                        onion_utils::Hop::Receive(next_hop_data) => {
                                // OUR PAYMENT!
-                               match self.construct_recv_pending_htlc_info(next_hop_data, shared_secret, msg.payment_hash, msg.amount_msat, msg.cltv_expiry, None) {
+                               match self.construct_recv_pending_htlc_info(next_hop_data, shared_secret, msg.payment_hash,
+                                       msg.amount_msat, msg.cltv_expiry, None, allow_underpay, msg.skimmed_fee_msat)
+                               {
                                        Ok(info) => {
                                                // Note that we could obviously respond immediately with an update_fulfill_htlc
                                                // message, however that would leak that we are the recipient of this payment, so
@@ -2465,10 +2911,10 @@ where
                                }
                        },
                        onion_utils::Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes } => {
-                               let new_pubkey = msg.onion_routing_packet.public_key.unwrap();
+                               debug_assert!(next_packet_pubkey_opt.is_some());
                                let outgoing_packet = msgs::OnionPacket {
                                        version: 0,
-                                       public_key: onion_utils::next_hop_packet_pubkey(&self.secp_ctx, new_pubkey, &shared_secret),
+                                       public_key: next_packet_pubkey_opt.unwrap_or(Err(secp256k1::Error::InvalidPublicKey)),
                                        hop_data: new_packet_bytes,
                                        hmac: next_hop_hmac.clone(),
                                };
@@ -2490,150 +2936,10 @@ where
                                        incoming_amt_msat: Some(msg.amount_msat),
                                        outgoing_amt_msat: next_hop_data.amt_to_forward,
                                        outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
+                                       skimmed_fee_msat: None,
                                })
                        }
-               };
-
-               if let &PendingHTLCStatus::Forward(PendingHTLCInfo { ref routing, ref outgoing_amt_msat, ref outgoing_cltv_value, .. }) = &pending_forward_info {
-                       // If short_channel_id is 0 here, we'll reject the HTLC as there cannot be a channel
-                       // with a short_channel_id of 0. This is important as various things later assume
-                       // short_channel_id is non-0 in any ::Forward.
-                       if let &PendingHTLCRouting::Forward { ref short_channel_id, .. } = routing {
-                               if let Some((err, mut code, chan_update)) = loop {
-                                       let id_option = self.short_to_chan_info.read().unwrap().get(short_channel_id).cloned();
-                                       let forwarding_chan_info_opt = match id_option {
-                                               None => { // unknown_next_peer
-                                                       // Note that this is likely a timing oracle for detecting whether an scid is a
-                                                       // phantom or an intercept.
-                                                       if (self.default_configuration.accept_intercept_htlcs &&
-                                                          fake_scid::is_valid_intercept(&self.fake_scid_rand_bytes, *short_channel_id, &self.genesis_hash)) ||
-                                                          fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, *short_channel_id, &self.genesis_hash)
-                                                       {
-                                                               None
-                                                       } else {
-                                                               break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
-                                                       }
-                                               },
-                                               Some((cp_id, id)) => Some((cp_id.clone(), id.clone())),
-                                       };
-                                       let chan_update_opt = if let Some((counterparty_node_id, forwarding_id)) = forwarding_chan_info_opt {
-                                               let per_peer_state = self.per_peer_state.read().unwrap();
-                                               let peer_state_mutex_opt = per_peer_state.get(&counterparty_node_id);
-                                               if peer_state_mutex_opt.is_none() {
-                                                       break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
-                                               }
-                                               let mut peer_state_lock = peer_state_mutex_opt.unwrap().lock().unwrap();
-                                               let peer_state = &mut *peer_state_lock;
-                                               let chan = match peer_state.channel_by_id.get_mut(&forwarding_id) {
-                                                       None => {
-                                                               // Channel was removed. The short_to_chan_info and channel_by_id maps
-                                                               // have no consistency guarantees.
-                                                               break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
-                                                       },
-                                                       Some(chan) => chan
-                                               };
-                                               if !chan.should_announce() && !self.default_configuration.accept_forwards_to_priv_channels {
-                                                       // Note that the behavior here should be identical to the above block - we
-                                                       // should NOT reveal the existence or non-existence of a private channel if
-                                                       // we don't allow forwards outbound over them.
-                                                       break Some(("Refusing to forward to a private channel based on our config.", 0x4000 | 10, None));
-                                               }
-                                               if chan.get_channel_type().supports_scid_privacy() && *short_channel_id != chan.outbound_scid_alias() {
-                                                       // `option_scid_alias` (referred to in LDK as `scid_privacy`) means
-                                                       // "refuse to forward unless the SCID alias was used", so we pretend
-                                                       // we don't have the channel here.
-                                                       break Some(("Refusing to forward over real channel SCID as our counterparty requested.", 0x4000 | 10, None));
-                                               }
-                                               let chan_update_opt = self.get_channel_update_for_onion(*short_channel_id, chan).ok();
-
-                                               // Note that we could technically not return an error yet here and just hope
-                                               // that the connection is reestablished or monitor updated by the time we get
-                                               // around to doing the actual forward, but better to fail early if we can and
-                                               // hopefully an attacker trying to path-trace payments cannot make this occur
-                                               // on a small/per-node/per-channel scale.
-                                               if !chan.is_live() { // channel_disabled
-                                                       // If the channel_update we're going to return is disabled (i.e. the
-                                                       // peer has been disabled for some time), return `channel_disabled`,
-                                                       // otherwise return `temporary_channel_failure`.
-                                                       if chan_update_opt.as_ref().map(|u| u.contents.flags & 2 == 2).unwrap_or(false) {
-                                                               break Some(("Forwarding channel has been disconnected for some time.", 0x1000 | 20, chan_update_opt));
-                                                       } else {
-                                                               break Some(("Forwarding channel is not in a ready state.", 0x1000 | 7, chan_update_opt));
-                                                       }
-                                               }
-                                               if *outgoing_amt_msat < chan.get_counterparty_htlc_minimum_msat() { // amount_below_minimum
-                                                       break Some(("HTLC amount was below the htlc_minimum_msat", 0x1000 | 11, chan_update_opt));
-                                               }
-                                               if let Err((err, code)) = chan.htlc_satisfies_config(&msg, *outgoing_amt_msat, *outgoing_cltv_value) {
-                                                       break Some((err, code, chan_update_opt));
-                                               }
-                                               chan_update_opt
-                                       } else {
-                                               if (msg.cltv_expiry as u64) < (*outgoing_cltv_value) as u64 + MIN_CLTV_EXPIRY_DELTA as u64 {
-                                                       // We really should set `incorrect_cltv_expiry` here but as we're not
-                                                       // forwarding over a real channel we can't generate a channel_update
-                                                       // for it. Instead we just return a generic temporary_node_failure.
-                                                       break Some((
-                                                               "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
-                                                               0x2000 | 2, None,
-                                                       ));
-                                               }
-                                               None
-                                       };
-
-                                       let cur_height = self.best_block.read().unwrap().height() + 1;
-                                       // Theoretically, channel counterparty shouldn't send us a HTLC expiring now,
-                                       // but we want to be robust wrt to counterparty packet sanitization (see
-                                       // HTLC_FAIL_BACK_BUFFER rationale).
-                                       if msg.cltv_expiry <= cur_height + HTLC_FAIL_BACK_BUFFER as u32 { // expiry_too_soon
-                                               break Some(("CLTV expiry is too close", 0x1000 | 14, chan_update_opt));
-                                       }
-                                       if msg.cltv_expiry > cur_height + CLTV_FAR_FAR_AWAY as u32 { // expiry_too_far
-                                               break Some(("CLTV expiry is too far in the future", 21, None));
-                                       }
-                                       // If the HTLC expires ~now, don't bother trying to forward it to our
-                                       // counterparty. They should fail it anyway, but we don't want to bother with
-                                       // the round-trips or risk them deciding they definitely want the HTLC and
-                                       // force-closing to ensure they get it if we're offline.
-                                       // We previously had a much more aggressive check here which tried to ensure
-                                       // our counterparty receives an HTLC which has *our* risk threshold met on it,
-                                       // but there is no need to do that, and since we're a bit conservative with our
-                                       // risk threshold it just results in failing to forward payments.
-                                       if (*outgoing_cltv_value) as u64 <= (cur_height + LATENCY_GRACE_PERIOD_BLOCKS) as u64 {
-                                               break Some(("Outgoing CLTV value is too soon", 0x1000 | 14, chan_update_opt));
-                                       }
-
-                                       break None;
-                               }
-                               {
-                                       let mut res = VecWriter(Vec::with_capacity(chan_update.serialized_length() + 2 + 8 + 2));
-                                       if let Some(chan_update) = chan_update {
-                                               if code == 0x1000 | 11 || code == 0x1000 | 12 {
-                                                       msg.amount_msat.write(&mut res).expect("Writes cannot fail");
-                                               }
-                                               else if code == 0x1000 | 13 {
-                                                       msg.cltv_expiry.write(&mut res).expect("Writes cannot fail");
-                                               }
-                                               else if code == 0x1000 | 20 {
-                                                       // TODO: underspecified, follow https://github.com/lightning/bolts/issues/791
-                                                       0u16.write(&mut res).expect("Writes cannot fail");
-                                               }
-                                               (chan_update.serialized_length() as u16 + 2).write(&mut res).expect("Writes cannot fail");
-                                               msgs::ChannelUpdate::TYPE.write(&mut res).expect("Writes cannot fail");
-                                               chan_update.write(&mut res).expect("Writes cannot fail");
-                                       } else if code & 0x1000 == 0x1000 {
-                                               // If we're trying to return an error that requires a `channel_update` but
-                                               // we're forwarding to a phantom or intercept "channel" (i.e. cannot
-                                               // generate an update), just use the generic "temporary_node_failure"
-                                               // instead.
-                                               code = 0x2000 | 2;
-                                       }
-                                       return_err!(err, code, &res.0[..]);
-                               }
-                       }
                }
-
-               pending_forward_info
        }
 
        /// Gets the current [`channel_update`] for the given channel. This first checks if the channel is
@@ -2647,16 +2953,16 @@ where
        /// [`channel_update`]: msgs::ChannelUpdate
        /// [`internal_closing_signed`]: Self::internal_closing_signed
        fn get_channel_update_for_broadcast(&self, chan: &Channel<<SP::Target as SignerProvider>::Signer>) -> Result<msgs::ChannelUpdate, LightningError> {
-               if !chan.should_announce() {
+               if !chan.context.should_announce() {
                        return Err(LightningError {
                                err: "Cannot broadcast a channel_update for a private channel".to_owned(),
                                action: msgs::ErrorAction::IgnoreError
                        });
                }
-               if chan.get_short_channel_id().is_none() {
+               if chan.context.get_short_channel_id().is_none() {
                        return Err(LightningError{err: "Channel not yet established".to_owned(), action: msgs::ErrorAction::IgnoreError});
                }
-               log_trace!(self.logger, "Attempting to generate broadcast channel update for channel {}", log_bytes!(chan.channel_id()));
+               log_trace!(self.logger, "Attempting to generate broadcast channel update for channel {}", log_bytes!(chan.context.channel_id()));
                self.get_channel_update_for_unicast(chan)
        }
 
@@ -2672,19 +2978,20 @@ where
        /// [`channel_update`]: msgs::ChannelUpdate
        /// [`internal_closing_signed`]: Self::internal_closing_signed
        fn get_channel_update_for_unicast(&self, chan: &Channel<<SP::Target as SignerProvider>::Signer>) -> Result<msgs::ChannelUpdate, LightningError> {
-               log_trace!(self.logger, "Attempting to generate channel update for channel {}", log_bytes!(chan.channel_id()));
-               let short_channel_id = match chan.get_short_channel_id().or(chan.latest_inbound_scid_alias()) {
+               log_trace!(self.logger, "Attempting to generate channel update for channel {}", log_bytes!(chan.context.channel_id()));
+               let short_channel_id = match chan.context.get_short_channel_id().or(chan.context.latest_inbound_scid_alias()) {
                        None => return Err(LightningError{err: "Channel not yet established".to_owned(), action: msgs::ErrorAction::IgnoreError}),
                        Some(id) => id,
                };
 
                self.get_channel_update_for_onion(short_channel_id, chan)
        }
+
        fn get_channel_update_for_onion(&self, short_channel_id: u64, chan: &Channel<<SP::Target as SignerProvider>::Signer>) -> Result<msgs::ChannelUpdate, LightningError> {
-               log_trace!(self.logger, "Generating channel update for channel {}", log_bytes!(chan.channel_id()));
-               let were_node_one = self.our_network_pubkey.serialize()[..] < chan.get_counterparty_node_id().serialize()[..];
+               log_trace!(self.logger, "Generating channel update for channel {}", log_bytes!(chan.context.channel_id()));
+               let were_node_one = self.our_network_pubkey.serialize()[..] < chan.context.get_counterparty_node_id().serialize()[..];
 
-               let enabled = chan.is_usable() && match chan.channel_update_status() {
+               let enabled = chan.context.is_usable() && match chan.channel_update_status() {
                        ChannelUpdateStatus::Enabled => true,
                        ChannelUpdateStatus::DisabledStaged(_) => true,
                        ChannelUpdateStatus::Disabled => false,
@@ -2694,13 +3001,13 @@ where
                let unsigned = msgs::UnsignedChannelUpdate {
                        chain_hash: self.genesis_hash,
                        short_channel_id,
-                       timestamp: chan.get_update_time_counter(),
+                       timestamp: chan.context.get_update_time_counter(),
                        flags: (!were_node_one) as u8 | ((!enabled as u8) << 1),
-                       cltv_expiry_delta: chan.get_cltv_expiry_delta(),
-                       htlc_minimum_msat: chan.get_counterparty_htlc_minimum_msat(),
-                       htlc_maximum_msat: chan.get_announced_htlc_max_msat(),
-                       fee_base_msat: chan.get_outbound_forwarding_fee_base_msat(),
-                       fee_proportional_millionths: chan.get_fee_proportional_millionths(),
+                       cltv_expiry_delta: chan.context.get_cltv_expiry_delta(),
+                       htlc_minimum_msat: chan.context.get_counterparty_htlc_minimum_msat(),
+                       htlc_maximum_msat: chan.context.get_announced_htlc_max_msat(),
+                       fee_base_msat: chan.context.get_outbound_forwarding_fee_base_msat(),
+                       fee_proportional_millionths: chan.context.get_fee_proportional_millionths(),
                        excess_data: Vec::new(),
                };
                // Panic on failure to signal LDK should be restarted to retry signing the `ChannelUpdate`.
@@ -2748,32 +3055,31 @@ where
                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                        let peer_state = &mut *peer_state_lock;
                        if let hash_map::Entry::Occupied(mut chan) = peer_state.channel_by_id.entry(id) {
-                               if !chan.get().is_live() {
+                               if !chan.get().context.is_live() {
                                        return Err(APIError::ChannelUnavailable{err: "Peer for first hop currently disconnected".to_owned()});
                                }
-                               let funding_txo = chan.get().get_funding_txo().unwrap();
+                               let funding_txo = chan.get().context.get_funding_txo().unwrap();
                                let send_res = chan.get_mut().send_htlc_and_commit(htlc_msat, payment_hash.clone(),
                                        htlc_cltv, HTLCSource::OutboundRoute {
                                                path: path.clone(),
                                                session_priv: session_priv.clone(),
                                                first_hop_htlc_msat: htlc_msat,
                                                payment_id,
-                                       }, onion_packet, &self.logger);
+                                       }, onion_packet, None, &self.logger);
                                match break_chan_entry!(self, send_res, chan) {
                                        Some(monitor_update) => {
-                                               let update_id = monitor_update.update_id;
-                                               let update_res = self.chain_monitor.update_channel(funding_txo, monitor_update);
-                                               if let Err(e) = handle_new_monitor_update!(self, update_res, update_id, peer_state_lock, peer_state, per_peer_state, chan) {
-                                                       break Err(e);
-                                               }
-                                               if update_res == ChannelMonitorUpdateStatus::InProgress {
-                                                       // Note that MonitorUpdateInProgress here indicates (per function
-                                                       // docs) that we will resend the commitment update once monitor
-                                                       // updating completes. Therefore, we must return an error
-                                                       // indicating that it is unsafe to retry the payment wholesale,
-                                                       // which we do in the send_payment check for
-                                                       // MonitorUpdateInProgress, below.
-                                                       return Err(APIError::MonitorUpdateInProgress);
+                                               match handle_new_monitor_update!(self, funding_txo, monitor_update, peer_state_lock, peer_state, per_peer_state, chan) {
+                                                       Err(e) => break Err(e),
+                                                       Ok(false) => {
+                                                               // Note that MonitorUpdateInProgress here indicates (per function
+                                                               // docs) that we will resend the commitment update once monitor
+                                                               // updating completes. Therefore, we must return an error
+                                                               // indicating that it is unsafe to retry the payment wholesale,
+                                                               // which we do in the send_payment check for
+                                                               // MonitorUpdateInProgress, below.
+                                                               return Err(APIError::MonitorUpdateInProgress);
+                                                       },
+                                                       Ok(true) => {},
                                                }
                                        },
                                        None => { },
@@ -2849,18 +3155,18 @@ where
        /// [`ChannelMonitorUpdateStatus::InProgress`]: crate::chain::ChannelMonitorUpdateStatus::InProgress
        pub fn send_payment_with_route(&self, route: &Route, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields, payment_id: PaymentId) -> Result<(), PaymentSendFailure> {
                let best_block_height = self.best_block.read().unwrap().height();
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments
                        .send_payment_with_route(route, payment_hash, recipient_onion, payment_id, &self.entropy_source, &self.node_signer, best_block_height,
                                |path, payment_hash, recipient_onion, total_value, cur_height, payment_id, keysend_preimage, session_priv|
                                self.send_payment_along_path(path, payment_hash, recipient_onion, total_value, cur_height, payment_id, keysend_preimage, session_priv))
        }
 
-       /// Similar to [`ChannelManager::send_payment`], but will automatically find a route based on
+       /// Similar to [`ChannelManager::send_payment_with_route`], but will automatically find a route based on
        /// `route_params` and retry failed payment paths based on `retry_strategy`.
        pub fn send_payment(&self, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields, payment_id: PaymentId, route_params: RouteParameters, retry_strategy: Retry) -> Result<(), RetryableSendFailure> {
                let best_block_height = self.best_block.read().unwrap().height();
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments
                        .send_payment(payment_hash, recipient_onion, payment_id, retry_strategy, route_params,
                                &self.router, self.list_usable_channels(), || self.compute_inflight_htlcs(),
@@ -2873,7 +3179,7 @@ where
        #[cfg(test)]
        pub(super) fn test_send_payment_internal(&self, route: &Route, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields, keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>, onion_session_privs: Vec<[u8; 32]>) -> Result<(), PaymentSendFailure> {
                let best_block_height = self.best_block.read().unwrap().height();
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments.test_send_payment_internal(route, payment_hash, recipient_onion, keysend_preimage, payment_id, recv_value_msat, onion_session_privs, &self.node_signer, best_block_height,
                        |path, payment_hash, recipient_onion, total_value, cur_height, payment_id, keysend_preimage, session_priv|
                        self.send_payment_along_path(path, payment_hash, recipient_onion, total_value, cur_height, payment_id, keysend_preimage, session_priv))
@@ -2908,7 +3214,7 @@ where
        /// [`Event::PaymentFailed`]: events::Event::PaymentFailed
        /// [`Event::PaymentSent`]: events::Event::PaymentSent
        pub fn abandon_payment(&self, payment_id: PaymentId) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments.abandon_payment(payment_id, PaymentFailureReason::UserAbandoned, &self.pending_events);
        }
 
@@ -2924,12 +3230,10 @@ where
        /// Similar to regular payments, you MUST NOT reuse a `payment_preimage` value. See
        /// [`send_payment`] for more information about the risks of duplicate preimage usage.
        ///
-       /// Note that `route` must have exactly one path.
-       ///
        /// [`send_payment`]: Self::send_payment
        pub fn send_spontaneous_payment(&self, route: &Route, payment_preimage: Option<PaymentPreimage>, recipient_onion: RecipientOnionFields, payment_id: PaymentId) -> Result<PaymentHash, PaymentSendFailure> {
                let best_block_height = self.best_block.read().unwrap().height();
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments.send_spontaneous_payment_with_route(
                        route, payment_preimage, recipient_onion, payment_id, &self.entropy_source,
                        &self.node_signer, best_block_height,
@@ -2946,7 +3250,7 @@ where
        /// [`PaymentParameters::for_keysend`]: crate::routing::router::PaymentParameters::for_keysend
        pub fn send_spontaneous_payment_with_retry(&self, payment_preimage: Option<PaymentPreimage>, recipient_onion: RecipientOnionFields, payment_id: PaymentId, route_params: RouteParameters, retry_strategy: Retry) -> Result<PaymentHash, RetryableSendFailure> {
                let best_block_height = self.best_block.read().unwrap().height();
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments.send_spontaneous_payment(payment_preimage, recipient_onion,
                        payment_id, retry_strategy, route_params, &self.router, self.list_usable_channels(),
                        || self.compute_inflight_htlcs(),  &self.entropy_source, &self.node_signer, best_block_height,
@@ -2960,7 +3264,7 @@ where
        /// us to easily discern them from real payments.
        pub fn send_probe(&self, path: Path) -> Result<(PaymentHash, PaymentId), PaymentSendFailure> {
                let best_block_height = self.best_block.read().unwrap().height();
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments.send_probe(path, self.probing_cookie_secret, &self.entropy_source, &self.node_signer, best_block_height,
                        |path, payment_hash, recipient_onion, total_value, cur_height, payment_id, keysend_preimage, session_priv|
                        self.send_payment_along_path(path, payment_hash, recipient_onion, total_value, cur_height, payment_id, keysend_preimage, session_priv))
@@ -2975,7 +3279,7 @@ where
 
        /// Handles the generation of a funding transaction, optionally (for tests) with a function
        /// which checks the correctness of the funding transaction given the associated channel.
-       fn funding_transaction_generated_intern<FundingOutput: Fn(&Channel<<SP::Target as SignerProvider>::Signer>, &Transaction) -> Result<OutPoint, APIError>>(
+       fn funding_transaction_generated_intern<FundingOutput: Fn(&OutboundV1Channel<<SP::Target as SignerProvider>::Signer>, &Transaction) -> Result<OutPoint, APIError>>(
                &self, temporary_channel_id: &[u8; 32], counterparty_node_id: &PublicKey, funding_transaction: Transaction, find_funding_output: FundingOutput
        ) -> Result<(), APIError> {
                let per_peer_state = self.per_peer_state.read().unwrap();
@@ -2984,21 +3288,24 @@ where
 
                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                let peer_state = &mut *peer_state_lock;
-               let (msg, chan) = match peer_state.channel_by_id.remove(temporary_channel_id) {
-                       Some(mut chan) => {
+               let (chan, msg) = match peer_state.outbound_v1_channel_by_id.remove(temporary_channel_id) {
+                       Some(chan) => {
                                let funding_txo = find_funding_output(&chan, &funding_transaction)?;
 
                                let funding_res = chan.get_outbound_funding_created(funding_transaction, funding_txo, &self.logger)
-                                       .map_err(|e| if let ChannelError::Close(msg) = e {
-                                               MsgHandleErrInternal::from_finish_shutdown(msg, chan.channel_id(), chan.get_user_id(), chan.force_shutdown(true), None)
+                                       .map_err(|(mut chan, e)| if let ChannelError::Close(msg) = e {
+                                               let channel_id = chan.context.channel_id();
+                                               let user_id = chan.context.get_user_id();
+                                               let shutdown_res = chan.context.force_shutdown(false);
+                                               (chan, MsgHandleErrInternal::from_finish_shutdown(msg, channel_id, user_id, shutdown_res, None))
                                        } else { unreachable!(); });
                                match funding_res {
-                                       Ok(funding_msg) => (funding_msg, chan),
-                                       Err(_) => {
+                                       Ok((chan, funding_msg)) => (chan, funding_msg),
+                                       Err((chan, err)) => {
                                                mem::drop(peer_state_lock);
                                                mem::drop(per_peer_state);
 
-                                               let _ = handle_error!(self, funding_res, chan.get_counterparty_node_id());
+                                               let _: Result<(), _> = handle_error!(self, Err(err), chan.context.get_counterparty_node_id());
                                                return Err(APIError::ChannelUnavailable {
                                                        err: "Signer refused to sign the initial commitment transaction".to_owned()
                                                });
@@ -3015,16 +3322,16 @@ where
                };
 
                peer_state.pending_msg_events.push(events::MessageSendEvent::SendFundingCreated {
-                       node_id: chan.get_counterparty_node_id(),
+                       node_id: chan.context.get_counterparty_node_id(),
                        msg,
                });
-               match peer_state.channel_by_id.entry(chan.channel_id()) {
+               match peer_state.channel_by_id.entry(chan.context.channel_id()) {
                        hash_map::Entry::Occupied(_) => {
                                panic!("Generated duplicate funding txid?");
                        },
                        hash_map::Entry::Vacant(e) => {
                                let mut id_to_peer = self.id_to_peer.lock().unwrap();
-                               if id_to_peer.insert(chan.channel_id(), chan.get_counterparty_node_id()).is_some() {
+                               if id_to_peer.insert(chan.context.channel_id(), chan.context.get_counterparty_node_id()).is_some() {
                                        panic!("id_to_peer map already contained funding txid, which shouldn't be possible");
                                }
                                e.insert(chan);
@@ -3071,7 +3378,7 @@ where
        /// [`Event::FundingGenerationReady`]: crate::events::Event::FundingGenerationReady
        /// [`Event::ChannelClosed`]: crate::events::Event::ChannelClosed
        pub fn funding_transaction_generated(&self, temporary_channel_id: &[u8; 32], counterparty_node_id: &PublicKey, funding_transaction: Transaction) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                for inp in funding_transaction.input.iter() {
                        if inp.witness.is_empty() {
@@ -3100,9 +3407,9 @@ where
                        }
 
                        let mut output_index = None;
-                       let expected_spk = chan.get_funding_redeemscript().to_v0_p2wsh();
+                       let expected_spk = chan.context.get_funding_redeemscript().to_v0_p2wsh();
                        for (idx, outp) in tx.output.iter().enumerate() {
-                               if outp.script_pubkey == expected_spk && outp.value == chan.get_value_satoshis() {
+                               if outp.script_pubkey == expected_spk && outp.value == chan.context.get_value_satoshis() {
                                        if output_index.is_some() {
                                                return Err(APIError::APIMisuseError {
                                                        err: "Multiple outputs matched the expected script and value".to_owned()
@@ -3120,7 +3427,7 @@ where
                })
        }
 
-       /// Atomically updates the [`ChannelConfig`] for the given channels.
+       /// Atomically applies partial updates to the [`ChannelConfig`] of the given channels.
        ///
        /// Once the updates are applied, each eligible channel (advertised with a known short channel
        /// ID and a change in [`forwarding_fee_proportional_millionths`], [`forwarding_fee_base_msat`],
@@ -3142,18 +3449,16 @@ where
        /// [`ChannelUpdate`]: msgs::ChannelUpdate
        /// [`ChannelUnavailable`]: APIError::ChannelUnavailable
        /// [`APIMisuseError`]: APIError::APIMisuseError
-       pub fn update_channel_config(
-               &self, counterparty_node_id: &PublicKey, channel_ids: &[[u8; 32]], config: &ChannelConfig,
+       pub fn update_partial_channel_config(
+               &self, counterparty_node_id: &PublicKey, channel_ids: &[[u8; 32]], config_update: &ChannelConfigUpdate,
        ) -> Result<(), APIError> {
-               if config.cltv_expiry_delta < MIN_CLTV_EXPIRY_DELTA {
+               if config_update.cltv_expiry_delta.map(|delta| delta < MIN_CLTV_EXPIRY_DELTA).unwrap_or(false) {
                        return Err(APIError::APIMisuseError {
                                err: format!("The chosen CLTV expiry delta is below the minimum of {}", MIN_CLTV_EXPIRY_DELTA),
                        });
                }
 
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(
-                       &self.total_consistency_lock, &self.persistence_notifier,
-               );
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let per_peer_state = self.per_peer_state.read().unwrap();
                let peer_state_mutex = per_peer_state.get(counterparty_node_id)
                        .ok_or_else(|| APIError::ChannelUnavailable { err: format!("Can't find a peer matching the passed counterparty node_id {}", counterparty_node_id) })?;
@@ -3168,14 +3473,16 @@ where
                }
                for channel_id in channel_ids {
                        let channel = peer_state.channel_by_id.get_mut(channel_id).unwrap();
-                       if !channel.update_config(config) {
+                       let mut config = channel.context.config();
+                       config.apply(config_update);
+                       if !channel.context.update_config(&config) {
                                continue;
                        }
                        if let Ok(msg) = self.get_channel_update_for_broadcast(channel) {
                                peer_state.pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate { msg });
                        } else if let Ok(msg) = self.get_channel_update_for_unicast(channel) {
                                peer_state.pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
-                                       node_id: channel.get_counterparty_node_id(),
+                                       node_id: channel.context.get_counterparty_node_id(),
                                        msg,
                                });
                        }
@@ -3183,6 +3490,34 @@ where
                Ok(())
        }
 
+       /// Atomically updates the [`ChannelConfig`] for the given channels.
+       ///
+       /// Once the updates are applied, each eligible channel (advertised with a known short channel
+       /// ID and a change in [`forwarding_fee_proportional_millionths`], [`forwarding_fee_base_msat`],
+       /// or [`cltv_expiry_delta`]) has a [`BroadcastChannelUpdate`] event message generated
+       /// containing the new [`ChannelUpdate`] message which should be broadcast to the network.
+       ///
+       /// Returns [`ChannelUnavailable`] when a channel is not found or an incorrect
+       /// `counterparty_node_id` is provided.
+       ///
+       /// Returns [`APIMisuseError`] when a [`cltv_expiry_delta`] update is to be applied with a value
+       /// below [`MIN_CLTV_EXPIRY_DELTA`].
+       ///
+       /// If an error is returned, none of the updates should be considered applied.
+       ///
+       /// [`forwarding_fee_proportional_millionths`]: ChannelConfig::forwarding_fee_proportional_millionths
+       /// [`forwarding_fee_base_msat`]: ChannelConfig::forwarding_fee_base_msat
+       /// [`cltv_expiry_delta`]: ChannelConfig::cltv_expiry_delta
+       /// [`BroadcastChannelUpdate`]: events::MessageSendEvent::BroadcastChannelUpdate
+       /// [`ChannelUpdate`]: msgs::ChannelUpdate
+       /// [`ChannelUnavailable`]: APIError::ChannelUnavailable
+       /// [`APIMisuseError`]: APIError::APIMisuseError
+       pub fn update_channel_config(
+               &self, counterparty_node_id: &PublicKey, channel_ids: &[[u8; 32]], config: &ChannelConfig,
+       ) -> Result<(), APIError> {
+               return self.update_partial_channel_config(counterparty_node_id, channel_ids, &(*config).into());
+       }
+
        /// Attempts to forward an intercepted HTLC over the provided channel id and with the provided
        /// amount to forward. Should only be called in response to an [`HTLCIntercepted`] event.
        ///
@@ -3196,17 +3531,20 @@ where
        /// [`ChannelManager::fail_intercepted_htlc`] MUST be called in response to the event.
        ///
        /// Note that LDK does not enforce fee requirements in `amt_to_forward_msat`, and will not stop
-       /// you from forwarding more than you received.
+       /// you from forwarding more than you received. See
+       /// [`HTLCIntercepted::expected_outbound_amount_msat`] for more on forwarding a different amount
+       /// than expected.
        ///
        /// Errors if the event was not handled in time, in which case the HTLC was automatically failed
        /// backwards.
        ///
        /// [`UserConfig::accept_intercept_htlcs`]: crate::util::config::UserConfig::accept_intercept_htlcs
        /// [`HTLCIntercepted`]: events::Event::HTLCIntercepted
+       /// [`HTLCIntercepted::expected_outbound_amount_msat`]: events::Event::HTLCIntercepted::expected_outbound_amount_msat
        // TODO: when we move to deciding the best outbound channel at forward time, only take
        // `next_node_id` and not `next_hop_channel_id`
        pub fn forward_intercepted_htlc(&self, intercept_id: InterceptId, next_hop_channel_id: &[u8; 32], next_node_id: PublicKey, amt_to_forward_msat: u64) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let next_hop_scid = {
                        let peer_state_lock = self.per_peer_state.read().unwrap();
@@ -3216,15 +3554,16 @@ where
                        let peer_state = &mut *peer_state_lock;
                        match peer_state.channel_by_id.get(next_hop_channel_id) {
                                Some(chan) => {
-                                       if !chan.is_usable() {
+                                       if !chan.context.is_usable() {
                                                return Err(APIError::ChannelUnavailable {
                                                        err: format!("Channel with id {} not fully established", log_bytes!(*next_hop_channel_id))
                                                })
                                        }
-                                       chan.get_short_channel_id().unwrap_or(chan.outbound_scid_alias())
+                                       chan.context.get_short_channel_id().unwrap_or(chan.context.outbound_scid_alias())
                                },
                                None => return Err(APIError::ChannelUnavailable {
-                                       err: format!("Channel with id {} not found for the passed counterparty node_id {}", log_bytes!(*next_hop_channel_id), next_node_id)
+                                       err: format!("Funded channel with id {} not found for the passed counterparty node_id {}. Channel may still be opening.",
+                                               log_bytes!(*next_hop_channel_id), next_node_id)
                                })
                        }
                };
@@ -3240,7 +3579,10 @@ where
                        },
                        _ => unreachable!() // Only `PendingHTLCRouting::Forward`s are intercepted
                };
+               let skimmed_fee_msat =
+                       payment.forward_info.outgoing_amt_msat.saturating_sub(amt_to_forward_msat);
                let pending_htlc_info = PendingHTLCInfo {
+                       skimmed_fee_msat: if skimmed_fee_msat == 0 { None } else { Some(skimmed_fee_msat) },
                        outgoing_amt_msat: amt_to_forward_msat, routing, ..payment.forward_info
                };
 
@@ -3262,7 +3604,7 @@ where
        ///
        /// [`HTLCIntercepted`]: events::Event::HTLCIntercepted
        pub fn fail_intercepted_htlc(&self, intercept_id: InterceptId) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let payment = self.pending_intercepted_htlcs.lock().unwrap().remove(&intercept_id)
                        .ok_or_else(|| APIError::APIMisuseError {
@@ -3291,7 +3633,7 @@ where
        /// Should only really ever be called in response to a PendingHTLCsForwardable event.
        /// Will likely generate further events.
        pub fn process_pending_htlc_forwards(&self) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let mut new_events = VecDeque::new();
                let mut failed_forwards = Vec::new();
@@ -3310,7 +3652,7 @@ where
                                                                                prev_short_channel_id, prev_htlc_id, prev_funding_outpoint, prev_user_channel_id,
                                                                                forward_info: PendingHTLCInfo {
                                                                                        routing, incoming_shared_secret, payment_hash, outgoing_amt_msat,
-                                                                                       outgoing_cltv_value, incoming_amt_msat: _
+                                                                                       outgoing_cltv_value, ..
                                                                                }
                                                                        }) => {
                                                                                macro_rules! failure_handler {
@@ -3372,7 +3714,10 @@ where
                                                                                                };
                                                                                                match next_hop {
                                                                                                        onion_utils::Hop::Receive(hop_data) => {
-                                                                                                               match self.construct_recv_pending_htlc_info(hop_data, incoming_shared_secret, payment_hash, outgoing_amt_msat, outgoing_cltv_value, Some(phantom_shared_secret)) {
+                                                                                                               match self.construct_recv_pending_htlc_info(hop_data,
+                                                                                                                       incoming_shared_secret, payment_hash, outgoing_amt_msat,
+                                                                                                                       outgoing_cltv_value, Some(phantom_shared_secret), false, None)
+                                                                                                               {
                                                                                                                        Ok(info) => phantom_receives.push((prev_short_channel_id, prev_funding_outpoint, prev_user_channel_id, vec![(info, prev_htlc_id)])),
                                                                                                                        Err(ReceiveError { err_code, err_data, msg }) => failed_payment!(msg, err_code, err_data, Some(phantom_shared_secret))
                                                                                                                }
@@ -3423,7 +3768,7 @@ where
                                                                                prev_short_channel_id, prev_htlc_id, prev_funding_outpoint, prev_user_channel_id: _,
                                                                                forward_info: PendingHTLCInfo {
                                                                                        incoming_shared_secret, payment_hash, outgoing_amt_msat, outgoing_cltv_value,
-                                                                                       routing: PendingHTLCRouting::Forward { onion_packet, .. }, incoming_amt_msat: _,
+                                                                                       routing: PendingHTLCRouting::Forward { onion_packet, .. }, skimmed_fee_msat, ..
                                                                                },
                                                                        }) => {
                                                                                log_trace!(self.logger, "Adding HTLC from short id {} with payment_hash {} to channel with short id {} after delay", prev_short_channel_id, log_bytes!(payment_hash.0), short_chan_id);
@@ -3437,7 +3782,7 @@ where
                                                                                });
                                                                                if let Err(e) = chan.get_mut().queue_add_htlc(outgoing_amt_msat,
                                                                                        payment_hash, outgoing_cltv_value, htlc_source.clone(),
-                                                                                       onion_packet, &self.logger)
+                                                                                       onion_packet, skimmed_fee_msat, &self.logger)
                                                                                {
                                                                                        if let ChannelError::Ignore(msg) = e {
                                                                                                log_trace!(self.logger, "Failed to forward HTLC with payment_hash {}: {}", log_bytes!(payment_hash.0), msg);
@@ -3447,7 +3792,7 @@ where
                                                                                        let (failure_code, data) = self.get_htlc_temp_fail_err_and_data(0x1000|7, short_chan_id, chan.get());
                                                                                        failed_forwards.push((htlc_source, payment_hash,
                                                                                                HTLCFailReason::reason(failure_code, data),
-                                                                                               HTLCDestination::NextHopChannel { node_id: Some(chan.get().get_counterparty_node_id()), channel_id: forward_chan_id }
+                                                                                               HTLCDestination::NextHopChannel { node_id: Some(chan.get().context.get_counterparty_node_id()), channel_id: forward_chan_id }
                                                                                        ));
                                                                                        continue;
                                                                                }
@@ -3481,7 +3826,8 @@ where
                                                        HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo {
                                                                prev_short_channel_id, prev_htlc_id, prev_funding_outpoint, prev_user_channel_id,
                                                                forward_info: PendingHTLCInfo {
-                                                                       routing, incoming_shared_secret, payment_hash, incoming_amt_msat, outgoing_amt_msat, ..
+                                                                       routing, incoming_shared_secret, payment_hash, incoming_amt_msat, outgoing_amt_msat,
+                                                                       skimmed_fee_msat, ..
                                                                }
                                                        }) => {
                                                                let (cltv_expiry, onion_payload, payment_data, phantom_shared_secret, mut onion_fields) = match routing {
@@ -3492,16 +3838,19 @@ where
                                                                                (incoming_cltv_expiry, OnionPayload::Invoice { _legacy_hop_data },
                                                                                        Some(payment_data), phantom_shared_secret, onion_fields)
                                                                        },
-                                                                       PendingHTLCRouting::ReceiveKeysend { payment_preimage, payment_metadata, incoming_cltv_expiry } => {
-                                                                               let onion_fields = RecipientOnionFields { payment_secret: None, payment_metadata };
+                                                                       PendingHTLCRouting::ReceiveKeysend { payment_data, payment_preimage, payment_metadata, incoming_cltv_expiry } => {
+                                                                               let onion_fields = RecipientOnionFields {
+                                                                                       payment_secret: payment_data.as_ref().map(|data| data.payment_secret),
+                                                                                       payment_metadata
+                                                                               };
                                                                                (incoming_cltv_expiry, OnionPayload::Spontaneous(payment_preimage),
-                                                                                       None, None, onion_fields)
+                                                                                       payment_data, None, onion_fields)
                                                                        },
                                                                        _ => {
                                                                                panic!("short_channel_id == 0 should imply any pending_forward entries are of type Receive");
                                                                        }
                                                                };
-                                                               let mut claimable_htlc = ClaimableHTLC {
+                                                               let claimable_htlc = ClaimableHTLC {
                                                                        prev_hop: HTLCPreviousHopData {
                                                                                short_channel_id: prev_short_channel_id,
                                                                                outpoint: prev_funding_outpoint,
@@ -3519,6 +3868,7 @@ where
                                                                        total_msat: if let Some(data) = &payment_data { data.total_msat } else { outgoing_amt_msat },
                                                                        cltv_expiry,
                                                                        onion_payload,
+                                                                       counterparty_skimmed_fee_msat: skimmed_fee_msat,
                                                                };
 
                                                                let mut committed_to_claimable = false;
@@ -3551,13 +3901,11 @@ where
                                                                }
 
                                                                macro_rules! check_total_value {
-                                                                       ($payment_data: expr, $payment_preimage: expr) => {{
+                                                                       ($purpose: expr) => {{
                                                                                let mut payment_claimable_generated = false;
-                                                                               let purpose = || {
-                                                                                       events::PaymentPurpose::InvoicePayment {
-                                                                                               payment_preimage: $payment_preimage,
-                                                                                               payment_secret: $payment_data.payment_secret,
-                                                                                       }
+                                                                               let is_keysend = match $purpose {
+                                                                                       events::PaymentPurpose::SpontaneousPayment(_) => true,
+                                                                                       events::PaymentPurpose::InvoicePayment { .. } => false,
                                                                                };
                                                                                let mut claimable_payments = self.claimable_payments.lock().unwrap();
                                                                                if claimable_payments.pending_claiming_payments.contains_key(&payment_hash) {
@@ -3569,9 +3917,18 @@ where
                                                                                        .or_insert_with(|| {
                                                                                                committed_to_claimable = true;
                                                                                                ClaimablePayment {
-                                                                                                       purpose: purpose(), htlcs: Vec::new(), onion_fields: None,
+                                                                                                       purpose: $purpose.clone(), htlcs: Vec::new(), onion_fields: None,
                                                                                                }
                                                                                        });
+                                                                               if $purpose != claimable_payment.purpose {
+                                                                                       let log_keysend = |keysend| if keysend { "keysend" } else { "non-keysend" };
+                                                                                       log_trace!(self.logger, "Failing new {} HTLC with payment_hash {} as we already had an existing {} HTLC with the same payment hash", log_keysend(is_keysend), log_bytes!(payment_hash.0), log_keysend(!is_keysend));
+                                                                                       fail_htlc!(claimable_htlc, payment_hash);
+                                                                               }
+                                                                               if !self.default_configuration.accept_mpp_keysend && is_keysend && !claimable_payment.htlcs.is_empty() {
+                                                                                       log_trace!(self.logger, "Failing new keysend HTLC with payment_hash {} as we already had an existing keysend HTLC with the same payment hash and our config states we don't accept MPP keysend", log_bytes!(payment_hash.0));
+                                                                                       fail_htlc!(claimable_htlc, payment_hash);
+                                                                               }
                                                                                if let Some(earlier_fields) = &mut claimable_payment.onion_fields {
                                                                                        if earlier_fields.check_merge(&mut onion_fields).is_err() {
                                                                                                fail_htlc!(claimable_htlc, payment_hash);
@@ -3580,38 +3937,27 @@ where
                                                                                        claimable_payment.onion_fields = Some(onion_fields);
                                                                                }
                                                                                let ref mut htlcs = &mut claimable_payment.htlcs;
-                                                                               if htlcs.len() == 1 {
-                                                                                       if let OnionPayload::Spontaneous(_) = htlcs[0].onion_payload {
-                                                                                               log_trace!(self.logger, "Failing new HTLC with payment_hash {} as we already had an existing keysend HTLC with the same payment hash", log_bytes!(payment_hash.0));
-                                                                                               fail_htlc!(claimable_htlc, payment_hash);
-                                                                                       }
-                                                                               }
                                                                                let mut total_value = claimable_htlc.sender_intended_value;
                                                                                let mut earliest_expiry = claimable_htlc.cltv_expiry;
                                                                                for htlc in htlcs.iter() {
                                                                                        total_value += htlc.sender_intended_value;
                                                                                        earliest_expiry = cmp::min(earliest_expiry, htlc.cltv_expiry);
-                                                                                       match &htlc.onion_payload {
-                                                                                               OnionPayload::Invoice { .. } => {
-                                                                                                       if htlc.total_msat != $payment_data.total_msat {
-                                                                                                               log_trace!(self.logger, "Failing HTLCs with payment_hash {} as the HTLCs had inconsistent total values (eg {} and {})",
-                                                                                                                       log_bytes!(payment_hash.0), $payment_data.total_msat, htlc.total_msat);
-                                                                                                               total_value = msgs::MAX_VALUE_MSAT;
-                                                                                                       }
-                                                                                                       if total_value >= msgs::MAX_VALUE_MSAT { break; }
-                                                                                               },
-                                                                                               _ => unreachable!(),
+                                                                                       if htlc.total_msat != claimable_htlc.total_msat {
+                                                                                               log_trace!(self.logger, "Failing HTLCs with payment_hash {} as the HTLCs had inconsistent total values (eg {} and {})",
+                                                                                                       log_bytes!(payment_hash.0), claimable_htlc.total_msat, htlc.total_msat);
+                                                                                               total_value = msgs::MAX_VALUE_MSAT;
                                                                                        }
+                                                                                       if total_value >= msgs::MAX_VALUE_MSAT { break; }
                                                                                }
                                                                                // The condition determining whether an MPP is complete must
                                                                                // match exactly the condition used in `timer_tick_occurred`
                                                                                if total_value >= msgs::MAX_VALUE_MSAT {
                                                                                        fail_htlc!(claimable_htlc, payment_hash);
-                                                                               } else if total_value - claimable_htlc.sender_intended_value >= $payment_data.total_msat {
+                                                                               } else if total_value - claimable_htlc.sender_intended_value >= claimable_htlc.total_msat {
                                                                                        log_trace!(self.logger, "Failing HTLC with payment_hash {} as payment is already claimable",
                                                                                                log_bytes!(payment_hash.0));
                                                                                        fail_htlc!(claimable_htlc, payment_hash);
-                                                                               } else if total_value >= $payment_data.total_msat {
+                                                                               } else if total_value >= claimable_htlc.total_msat {
                                                                                        #[allow(unused_assignments)] {
                                                                                                committed_to_claimable = true;
                                                                                        }
@@ -3619,11 +3965,16 @@ where
                                                                                        htlcs.push(claimable_htlc);
                                                                                        let amount_msat = htlcs.iter().map(|htlc| htlc.value).sum();
                                                                                        htlcs.iter_mut().for_each(|htlc| htlc.total_value_received = Some(amount_msat));
+                                                                                       let counterparty_skimmed_fee_msat = htlcs.iter()
+                                                                                               .map(|htlc| htlc.counterparty_skimmed_fee_msat.unwrap_or(0)).sum();
+                                                                                       debug_assert!(total_value.saturating_sub(amount_msat) <=
+                                                                                               counterparty_skimmed_fee_msat);
                                                                                        new_events.push_back((events::Event::PaymentClaimable {
                                                                                                receiver_node_id: Some(receiver_node_id),
                                                                                                payment_hash,
-                                                                                               purpose: purpose(),
+                                                                                               purpose: $purpose,
                                                                                                amount_msat,
+                                                                                               counterparty_skimmed_fee_msat,
                                                                                                via_channel_id: Some(prev_channel_id),
                                                                                                via_user_channel_id: Some(prev_user_channel_id),
                                                                                                claim_deadline: Some(earliest_expiry - HTLC_FAIL_BACK_BUFFER),
@@ -3670,49 +4021,23 @@ where
                                                                                                                fail_htlc!(claimable_htlc, payment_hash);
                                                                                                        }
                                                                                                }
-                                                                                               check_total_value!(payment_data, payment_preimage);
+                                                                                               let purpose = events::PaymentPurpose::InvoicePayment {
+                                                                                                       payment_preimage: payment_preimage.clone(),
+                                                                                                       payment_secret: payment_data.payment_secret,
+                                                                                               };
+                                                                                               check_total_value!(purpose);
                                                                                        },
                                                                                        OnionPayload::Spontaneous(preimage) => {
-                                                                                               let mut claimable_payments = self.claimable_payments.lock().unwrap();
-                                                                                               if claimable_payments.pending_claiming_payments.contains_key(&payment_hash) {
-                                                                                                       fail_htlc!(claimable_htlc, payment_hash);
-                                                                                               }
-                                                                                               match claimable_payments.claimable_payments.entry(payment_hash) {
-                                                                                                       hash_map::Entry::Vacant(e) => {
-                                                                                                               let amount_msat = claimable_htlc.value;
-                                                                                                               claimable_htlc.total_value_received = Some(amount_msat);
-                                                                                                               let claim_deadline = Some(claimable_htlc.cltv_expiry - HTLC_FAIL_BACK_BUFFER);
-                                                                                                               let purpose = events::PaymentPurpose::SpontaneousPayment(preimage);
-                                                                                                               e.insert(ClaimablePayment {
-                                                                                                                       purpose: purpose.clone(),
-                                                                                                                       onion_fields: Some(onion_fields.clone()),
-                                                                                                                       htlcs: vec![claimable_htlc],
-                                                                                                               });
-                                                                                                               let prev_channel_id = prev_funding_outpoint.to_channel_id();
-                                                                                                               new_events.push_back((events::Event::PaymentClaimable {
-                                                                                                                       receiver_node_id: Some(receiver_node_id),
-                                                                                                                       payment_hash,
-                                                                                                                       amount_msat,
-                                                                                                                       purpose,
-                                                                                                                       via_channel_id: Some(prev_channel_id),
-                                                                                                                       via_user_channel_id: Some(prev_user_channel_id),
-                                                                                                                       claim_deadline,
-                                                                                                                       onion_fields: Some(onion_fields),
-                                                                                                               }, None));
-                                                                                                       },
-                                                                                                       hash_map::Entry::Occupied(_) => {
-                                                                                                               log_trace!(self.logger, "Failing new keysend HTLC with payment_hash {} for a duplicative payment hash", log_bytes!(payment_hash.0));
-                                                                                                               fail_htlc!(claimable_htlc, payment_hash);
-                                                                                                       }
-                                                                                               }
+                                                                                               let purpose = events::PaymentPurpose::SpontaneousPayment(preimage);
+                                                                                               check_total_value!(purpose);
                                                                                        }
                                                                                }
                                                                        },
                                                                        hash_map::Entry::Occupied(inbound_payment) => {
-                                                                               if payment_data.is_none() {
+                                                                               if let OnionPayload::Spontaneous(_) = claimable_htlc.onion_payload {
                                                                                        log_trace!(self.logger, "Failing new keysend HTLC with payment_hash {} because we already have an inbound payment with the same payment hash", log_bytes!(payment_hash.0));
                                                                                        fail_htlc!(claimable_htlc, payment_hash);
-                                                                               };
+                                                                               }
                                                                                let payment_data = payment_data.unwrap();
                                                                                if inbound_payment.get().payment_secret != payment_data.payment_secret {
                                                                                        log_trace!(self.logger, "Failing new HTLC with payment_hash {} as it didn't match our expected payment secret.", log_bytes!(payment_hash.0));
@@ -3722,7 +4047,11 @@ where
                                                                                                log_bytes!(payment_hash.0), payment_data.total_msat, inbound_payment.get().min_value_msat.unwrap());
                                                                                        fail_htlc!(claimable_htlc, payment_hash);
                                                                                } else {
-                                                                                       let payment_claimable_generated = check_total_value!(payment_data, inbound_payment.get().payment_preimage);
+                                                                                       let purpose = events::PaymentPurpose::InvoicePayment {
+                                                                                               payment_preimage: inbound_payment.get().payment_preimage,
+                                                                                               payment_secret: payment_data.payment_secret,
+                                                                                       };
+                                                                                       let payment_claimable_generated = check_total_value!(purpose);
                                                                                        if payment_claimable_generated {
                                                                                                inbound_payment.remove_entry();
                                                                                        }
@@ -3762,52 +4091,85 @@ where
                events.append(&mut new_events);
        }
 
-       /// Free the background events, generally called from timer_tick_occurred.
-       ///
-       /// Exposed for testing to allow us to process events quickly without generating accidental
-       /// BroadcastChannelUpdate events in timer_tick_occurred.
+       /// Free the background events, generally called from [`PersistenceNotifierGuard`] constructors.
        ///
        /// Expects the caller to have a total_consistency_lock read lock.
-       fn process_background_events(&self) -> bool {
+       fn process_background_events(&self) -> NotifyOption {
+               debug_assert_ne!(self.total_consistency_lock.held_by_thread(), LockHeldState::NotHeldByThread);
+
+               #[cfg(debug_assertions)]
+               self.background_events_processed_since_startup.store(true, Ordering::Release);
+
                let mut background_events = Vec::new();
                mem::swap(&mut *self.pending_background_events.lock().unwrap(), &mut background_events);
                if background_events.is_empty() {
-                       return false;
+                       return NotifyOption::SkipPersist;
                }
 
                for event in background_events.drain(..) {
                        match event {
-                               BackgroundEvent::MonitorUpdateRegeneratedOnStartup((funding_txo, update)) => {
+                               BackgroundEvent::ClosingMonitorUpdateRegeneratedOnStartup((funding_txo, update)) => {
                                        // The channel has already been closed, so no use bothering to care about the
                                        // monitor updating completing.
                                        let _ = self.chain_monitor.update_channel(funding_txo, &update);
                                },
+                               BackgroundEvent::MonitorUpdateRegeneratedOnStartup { counterparty_node_id, funding_txo, update } => {
+                                       let mut updated_chan = false;
+                                       let res = {
+                                               let per_peer_state = self.per_peer_state.read().unwrap();
+                                               if let Some(peer_state_mutex) = per_peer_state.get(&counterparty_node_id) {
+                                                       let mut peer_state_lock = peer_state_mutex.lock().unwrap();
+                                                       let peer_state = &mut *peer_state_lock;
+                                                       match peer_state.channel_by_id.entry(funding_txo.to_channel_id()) {
+                                                               hash_map::Entry::Occupied(mut chan) => {
+                                                                       updated_chan = true;
+                                                                       handle_new_monitor_update!(self, funding_txo, update.clone(),
+                                                                               peer_state_lock, peer_state, per_peer_state, chan).map(|_| ())
+                                                               },
+                                                               hash_map::Entry::Vacant(_) => Ok(()),
+                                                       }
+                                               } else { Ok(()) }
+                                       };
+                                       if !updated_chan {
+                                               // TODO: Track this as in-flight even though the channel is closed.
+                                               let _ = self.chain_monitor.update_channel(funding_txo, &update);
+                                       }
+                                       // TODO: If this channel has since closed, we're likely providing a payment
+                                       // preimage update, which we must ensure is durable! We currently don't,
+                                       // however, ensure that.
+                                       if res.is_err() {
+                                               log_error!(self.logger,
+                                                       "Failed to provide ChannelMonitorUpdate to closed channel! This likely lost us a payment preimage!");
+                                       }
+                                       let _ = handle_error!(self, res, counterparty_node_id);
+                               },
                        }
                }
-               true
+               NotifyOption::DoPersist
        }
 
        #[cfg(any(test, feature = "_test_utils"))]
        /// Process background events, for functional testing
        pub fn test_process_background_events(&self) {
-               self.process_background_events();
+               let _lck = self.total_consistency_lock.read().unwrap();
+               let _ = self.process_background_events();
        }
 
        fn update_channel_fee(&self, chan_id: &[u8; 32], chan: &mut Channel<<SP::Target as SignerProvider>::Signer>, new_feerate: u32) -> NotifyOption {
-               if !chan.is_outbound() { return NotifyOption::SkipPersist; }
+               if !chan.context.is_outbound() { return NotifyOption::SkipPersist; }
                // If the feerate has decreased by less than half, don't bother
-               if new_feerate <= chan.get_feerate_sat_per_1000_weight() && new_feerate * 2 > chan.get_feerate_sat_per_1000_weight() {
+               if new_feerate <= chan.context.get_feerate_sat_per_1000_weight() && new_feerate * 2 > chan.context.get_feerate_sat_per_1000_weight() {
                        log_trace!(self.logger, "Channel {} does not qualify for a feerate change from {} to {}.",
-                               log_bytes!(chan_id[..]), chan.get_feerate_sat_per_1000_weight(), new_feerate);
+                               log_bytes!(chan_id[..]), chan.context.get_feerate_sat_per_1000_weight(), new_feerate);
                        return NotifyOption::SkipPersist;
                }
-               if !chan.is_live() {
+               if !chan.context.is_live() {
                        log_trace!(self.logger, "Channel {} does not qualify for a feerate change from {} to {} as it cannot currently be updated (probably the peer is disconnected).",
-                               log_bytes!(chan_id[..]), chan.get_feerate_sat_per_1000_weight(), new_feerate);
+                               log_bytes!(chan_id[..]), chan.context.get_feerate_sat_per_1000_weight(), new_feerate);
                        return NotifyOption::SkipPersist;
                }
                log_trace!(self.logger, "Channel {} qualifies for a feerate change from {} to {}.",
-                       log_bytes!(chan_id[..]), chan.get_feerate_sat_per_1000_weight(), new_feerate);
+                       log_bytes!(chan_id[..]), chan.context.get_feerate_sat_per_1000_weight(), new_feerate);
 
                chan.queue_update_fee(new_feerate, &self.logger);
                NotifyOption::DoPersist
@@ -3820,7 +4182,7 @@ where
        /// it wants to detect). Thus, we have a variant exposed here for its benefit.
        pub fn maybe_update_chan_fees(&self) {
                PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock, &self.persistence_notifier, || {
-                       let mut should_persist = NotifyOption::SkipPersist;
+                       let mut should_persist = self.process_background_events();
 
                        let new_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal);
 
@@ -3856,8 +4218,7 @@ where
        /// [`ChannelConfig`]: crate::util::config::ChannelConfig
        pub fn timer_tick_occurred(&self) {
                PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock, &self.persistence_notifier, || {
-                       let mut should_persist = NotifyOption::SkipPersist;
-                       if self.process_background_events() { should_persist = NotifyOption::DoPersist; }
+                       let mut should_persist = self.process_background_events();
 
                        let new_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal);
 
@@ -3882,13 +4243,13 @@ where
                                                }
 
                                                match chan.channel_update_status() {
-                                                       ChannelUpdateStatus::Enabled if !chan.is_live() => chan.set_channel_update_status(ChannelUpdateStatus::DisabledStaged(0)),
-                                                       ChannelUpdateStatus::Disabled if chan.is_live() => chan.set_channel_update_status(ChannelUpdateStatus::EnabledStaged(0)),
-                                                       ChannelUpdateStatus::DisabledStaged(_) if chan.is_live()
+                                                       ChannelUpdateStatus::Enabled if !chan.context.is_live() => chan.set_channel_update_status(ChannelUpdateStatus::DisabledStaged(0)),
+                                                       ChannelUpdateStatus::Disabled if chan.context.is_live() => chan.set_channel_update_status(ChannelUpdateStatus::EnabledStaged(0)),
+                                                       ChannelUpdateStatus::DisabledStaged(_) if chan.context.is_live()
                                                                => chan.set_channel_update_status(ChannelUpdateStatus::Enabled),
-                                                       ChannelUpdateStatus::EnabledStaged(_) if !chan.is_live()
+                                                       ChannelUpdateStatus::EnabledStaged(_) if !chan.context.is_live()
                                                                => chan.set_channel_update_status(ChannelUpdateStatus::Disabled),
-                                                       ChannelUpdateStatus::DisabledStaged(mut n) if !chan.is_live() => {
+                                                       ChannelUpdateStatus::DisabledStaged(mut n) if !chan.context.is_live() => {
                                                                n += 1;
                                                                if n >= DISABLE_GOSSIP_TICKS {
                                                                        chan.set_channel_update_status(ChannelUpdateStatus::Disabled);
@@ -3902,7 +4263,7 @@ where
                                                                        chan.set_channel_update_status(ChannelUpdateStatus::DisabledStaged(n));
                                                                }
                                                        },
-                                                       ChannelUpdateStatus::EnabledStaged(mut n) if chan.is_live() => {
+                                                       ChannelUpdateStatus::EnabledStaged(mut n) if chan.context.is_live() => {
                                                                n += 1;
                                                                if n >= ENABLE_GOSSIP_TICKS {
                                                                        chan.set_channel_update_status(ChannelUpdateStatus::Enabled);
@@ -3919,7 +4280,21 @@ where
                                                        _ => {},
                                                }
 
-                                               chan.maybe_expire_prev_config();
+                                               chan.context.maybe_expire_prev_config();
+
+                                               if chan.should_disconnect_peer_awaiting_response() {
+                                                       log_debug!(self.logger, "Disconnecting peer {} due to not making any progress on channel {}",
+                                                                       counterparty_node_id, log_bytes!(*chan_id));
+                                                       pending_msg_events.push(MessageSendEvent::HandleError {
+                                                               node_id: counterparty_node_id,
+                                                               action: msgs::ErrorAction::DisconnectPeerWithWarning {
+                                                                       msg: msgs::WarningMessage {
+                                                                               channel_id: *chan_id,
+                                                                               data: "Disconnecting due to timeout awaiting response".to_owned(),
+                                                                       },
+                                                               },
+                                                       });
+                                               }
 
                                                true
                                        });
@@ -4029,7 +4404,7 @@ where
        ///
        /// See [`FailureCode`] for valid failure codes.
        pub fn fail_htlc_backwards_with_reason(&self, payment_hash: &PaymentHash, failure_code: FailureCode) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let removed_source = self.claimable_payments.lock().unwrap().claimable_payments.remove(payment_hash);
                if let Some(payment) = removed_source {
@@ -4065,10 +4440,10 @@ where
                // guess somewhat. If its a public channel, we figure best to just use the real SCID (as
                // we're not leaking that we have a channel with the counterparty), otherwise we try to use
                // an inbound SCID alias before the real SCID.
-               let scid_pref = if chan.should_announce() {
-                       chan.get_short_channel_id().or(chan.latest_inbound_scid_alias())
+               let scid_pref = if chan.context.should_announce() {
+                       chan.context.get_short_channel_id().or(chan.context.latest_inbound_scid_alias())
                } else {
-                       chan.latest_inbound_scid_alias().or(chan.get_short_channel_id())
+                       chan.context.latest_inbound_scid_alias().or(chan.context.get_short_channel_id())
                };
                if let Some(scid) = scid_pref {
                        self.get_htlc_temp_fail_err_and_data(desired_err_code, scid, chan)
@@ -4206,7 +4581,7 @@ where
        pub fn claim_funds(&self, payment_preimage: PaymentPreimage) {
                let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let mut sources = {
                        let mut claimable_payments = self.claimable_payments.lock().unwrap();
@@ -4261,18 +4636,6 @@ where
                                break;
                        }
                        expected_amt_msat = htlc.total_value_received;
-
-                       if let OnionPayload::Spontaneous(_) = &htlc.onion_payload {
-                               // We don't currently support MPP for spontaneous payments, so just check
-                               // that there's one payment here and move on.
-                               if sources.len() != 1 {
-                                       log_error!(self.logger, "Somehow ended up with an MPP spontaneous payment - this should not be reachable!");
-                                       debug_assert!(false);
-                                       valid_mpp = false;
-                                       break;
-                               }
-                       }
-
                        claimable_amt_msat += htlc.value;
                }
                mem::drop(per_peer_state);
@@ -4342,7 +4705,7 @@ where
                                let mut peer_state_lock = peer_state_opt.unwrap();
                                let peer_state = &mut *peer_state_lock;
                                if let hash_map::Entry::Occupied(mut chan) = peer_state.channel_by_id.entry(chan_id) {
-                                       let counterparty_node_id = chan.get().get_counterparty_node_id();
+                                       let counterparty_node_id = chan.get().context.get_counterparty_node_id();
                                        let fulfill_res = chan.get_mut().get_update_fulfill_htlc_and_commit(prev_hop.htlc_id, payment_preimage, &self.logger);
 
                                        if let UpdateFulfillCommitFetch::NewClaim { htlc_value_msat, monitor_update } = fulfill_res {
@@ -4351,9 +4714,7 @@ where
                                                                log_bytes!(chan_id), action);
                                                        peer_state.monitor_update_blocked_actions.entry(chan_id).or_insert(Vec::new()).push(action);
                                                }
-                                               let update_id = monitor_update.update_id;
-                                               let update_res = self.chain_monitor.update_channel(prev_hop.outpoint, monitor_update);
-                                               let res = handle_new_monitor_update!(self, update_res, update_id, peer_state_lock,
+                                               let res = handle_new_monitor_update!(self, prev_hop.outpoint, monitor_update, peer_state_lock,
                                                        peer_state, per_peer_state, chan);
                                                if let Err(e) = res {
                                                        // TODO: This is a *critical* error - we probably updated the outbound edge
@@ -4411,16 +4772,16 @@ where
                                                                Some(claimed_htlc_value - forwarded_htlc_value)
                                                        } else { None };
 
-                                                       let prev_channel_id = Some(prev_outpoint.to_channel_id());
-                                                       let next_channel_id = Some(next_channel_id);
-
-                                                       Some(MonitorUpdateCompletionAction::EmitEvent { event: events::Event::PaymentForwarded {
-                                                               fee_earned_msat,
-                                                               claim_from_onchain_tx: from_onchain,
-                                                               prev_channel_id,
-                                                               next_channel_id,
-                                                               outbound_amount_forwarded_msat: forwarded_htlc_value_msat,
-                                                       }})
+                                                       Some(MonitorUpdateCompletionAction::EmitEventAndFreeOtherChannel {
+                                                               event: events::Event::PaymentForwarded {
+                                                                       fee_earned_msat,
+                                                                       claim_from_onchain_tx: from_onchain,
+                                                                       prev_channel_id: Some(prev_outpoint.to_channel_id()),
+                                                                       next_channel_id: Some(next_channel_id),
+                                                                       outbound_amount_forwarded_msat: forwarded_htlc_value_msat,
+                                                               },
+                                                               downstream_counterparty_and_funding_outpoint: None,
+                                                       })
                                                } else { None }
                                        });
                                if let Err((pk, err)) = res {
@@ -4447,8 +4808,13 @@ where
                                                }, None));
                                        }
                                },
-                               MonitorUpdateCompletionAction::EmitEvent { event } => {
+                               MonitorUpdateCompletionAction::EmitEventAndFreeOtherChannel {
+                                       event, downstream_counterparty_and_funding_outpoint
+                               } => {
                                        self.pending_events.lock().unwrap().push_back((event, None));
+                                       if let Some((node_id, funding_outpoint, blocker)) = downstream_counterparty_and_funding_outpoint {
+                                               self.handle_monitor_update_release(node_id, funding_outpoint, Some(blocker));
+                                       }
                                },
                        }
                }
@@ -4463,7 +4829,7 @@ where
                channel_ready: Option<msgs::ChannelReady>, announcement_sigs: Option<msgs::AnnouncementSignatures>)
        -> Option<(u64, OutPoint, u128, Vec<(PendingHTLCInfo, u64)>)> {
                log_trace!(self.logger, "Handling channel resumption for channel {} with {} RAA, {} commitment update, {} pending forwards, {}broadcasting funding, {} channel ready, {} announcement",
-                       log_bytes!(channel.channel_id()),
+                       log_bytes!(channel.context.channel_id()),
                        if raa.is_some() { "an" } else { "no" },
                        if commitment_update.is_some() { "a" } else { "no" }, pending_forwards.len(),
                        if funding_broadcastable.is_some() { "" } else { "not " },
@@ -4472,10 +4838,10 @@ where
 
                let mut htlc_forwards = None;
 
-               let counterparty_node_id = channel.get_counterparty_node_id();
+               let counterparty_node_id = channel.context.get_counterparty_node_id();
                if !pending_forwards.is_empty() {
-                       htlc_forwards = Some((channel.get_short_channel_id().unwrap_or(channel.outbound_scid_alias()),
-                               channel.get_funding_txo().unwrap(), channel.get_user_id(), pending_forwards));
+                       htlc_forwards = Some((channel.context.get_short_channel_id().unwrap_or(channel.context.outbound_scid_alias()),
+                               channel.context.get_funding_txo().unwrap(), channel.context.get_user_id(), pending_forwards));
                }
 
                if let Some(msg) = channel_ready {
@@ -4556,12 +4922,18 @@ where
                                hash_map::Entry::Vacant(_) => return,
                        }
                };
-               log_trace!(self.logger, "ChannelMonitor updated to {}. Current highest is {}",
-                       highest_applied_update_id, channel.get().get_latest_monitor_update_id());
-               if !channel.get().is_awaiting_monitor_update() || channel.get().get_latest_monitor_update_id() != highest_applied_update_id {
+               let remaining_in_flight =
+                       if let Some(pending) = peer_state.in_flight_monitor_updates.get_mut(funding_txo) {
+                               pending.retain(|upd| upd.update_id > highest_applied_update_id);
+                               pending.len()
+                       } else { 0 };
+               log_trace!(self.logger, "ChannelMonitor updated to {}. Current highest is {}. {} pending in-flight updates.",
+                       highest_applied_update_id, channel.get().context.get_latest_monitor_update_id(),
+                       remaining_in_flight);
+               if !channel.get().is_awaiting_monitor_update() || channel.get().context.get_latest_monitor_update_id() != highest_applied_update_id {
                        return;
                }
-               handle_monitor_update_completion!(self, highest_applied_update_id, peer_state_lock, peer_state, per_peer_state, channel.get_mut());
+               handle_monitor_update_completion!(self, peer_state_lock, peer_state, per_peer_state, channel.get_mut());
        }
 
        /// Accepts a request to open a channel after a [`Event::OpenChannelRequest`].
@@ -4607,25 +4979,26 @@ where
        }
 
        fn do_accept_inbound_channel(&self, temporary_channel_id: &[u8; 32], counterparty_node_id: &PublicKey, accept_0conf: bool, user_channel_id: u128) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
-               let peers_without_funded_channels = self.peers_without_funded_channels(|peer| !peer.channel_by_id.is_empty());
+               let peers_without_funded_channels =
+                       self.peers_without_funded_channels(|peer| { peer.total_channel_count() > 0 });
                let per_peer_state = self.per_peer_state.read().unwrap();
                let peer_state_mutex = per_peer_state.get(counterparty_node_id)
                        .ok_or_else(|| APIError::ChannelUnavailable { err: format!("Can't find a peer matching the passed counterparty node_id {}", counterparty_node_id) })?;
                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                let peer_state = &mut *peer_state_lock;
-               let is_only_peer_channel = peer_state.channel_by_id.len() == 1;
-               match peer_state.channel_by_id.entry(temporary_channel_id.clone()) {
+               let is_only_peer_channel = peer_state.total_channel_count() == 1;
+               match peer_state.inbound_v1_channel_by_id.entry(temporary_channel_id.clone()) {
                        hash_map::Entry::Occupied(mut channel) => {
-                               if !channel.get().inbound_is_awaiting_accept() {
+                               if !channel.get().is_awaiting_accept() {
                                        return Err(APIError::APIMisuseError { err: "The channel isn't currently awaiting to be accepted.".to_owned() });
                                }
                                if accept_0conf {
                                        channel.get_mut().set_0conf();
-                               } else if channel.get().get_channel_type().requires_zero_conf() {
+                               } else if channel.get().context.get_channel_type().requires_zero_conf() {
                                        let send_msg_err_event = events::MessageSendEvent::HandleError {
-                                               node_id: channel.get().get_counterparty_node_id(),
+                                               node_id: channel.get().context.get_counterparty_node_id(),
                                                action: msgs::ErrorAction::SendErrorMessage{
                                                        msg: msgs::ErrorMessage { channel_id: temporary_channel_id.clone(), data: "No zero confirmation channels accepted".to_owned(), }
                                                }
@@ -4639,7 +5012,7 @@ where
                                        // channels per-peer we can accept channels from a peer with existing ones.
                                        if is_only_peer_channel && peers_without_funded_channels >= MAX_UNFUNDED_CHANNEL_PEERS {
                                                let send_msg_err_event = events::MessageSendEvent::HandleError {
-                                                       node_id: channel.get().get_counterparty_node_id(),
+                                                       node_id: channel.get().context.get_counterparty_node_id(),
                                                        action: msgs::ErrorAction::SendErrorMessage{
                                                                msg: msgs::ErrorMessage { channel_id: temporary_channel_id.clone(), data: "Have too many peers with unfunded channels, not accepting new ones".to_owned(), }
                                                        }
@@ -4651,7 +5024,7 @@ where
                                }
 
                                peer_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
-                                       node_id: channel.get().get_counterparty_node_id(),
+                                       node_id: channel.get().context.get_counterparty_node_id(),
                                        msg: channel.get_mut().accept_inbound_channel(user_channel_id),
                                });
                        }
@@ -4677,7 +5050,7 @@ where
                                let peer = peer_mtx.lock().unwrap();
                                if !maybe_count_peer(&*peer) { continue; }
                                let num_unfunded_channels = Self::unfunded_channel_count(&peer, best_block_height);
-                               if num_unfunded_channels == peer.channel_by_id.len() {
+                               if num_unfunded_channels == peer.total_channel_count() {
                                        peers_without_funded_channels += 1;
                                }
                        }
@@ -4690,12 +5063,19 @@ where
        ) -> usize {
                let mut num_unfunded_channels = 0;
                for (_, chan) in peer.channel_by_id.iter() {
-                       if !chan.is_outbound() && chan.minimum_depth().unwrap_or(1) != 0 &&
-                               chan.get_funding_tx_confirmations(best_block_height) == 0
+                       // This covers non-zero-conf inbound `Channel`s that we are currently monitoring, but those
+                       // which have not yet had any confirmations on-chain.
+                       if !chan.context.is_outbound() && chan.context.minimum_depth().unwrap_or(1) != 0 &&
+                               chan.context.get_funding_tx_confirmations(best_block_height) == 0
                        {
                                num_unfunded_channels += 1;
                        }
                }
+               for (_, chan) in peer.inbound_v1_channel_by_id.iter() {
+                       if chan.context.minimum_depth().unwrap_or(1) != 0 {
+                               num_unfunded_channels += 1;
+                       }
+               }
                num_unfunded_channels
        }
 
@@ -4716,7 +5096,8 @@ where
                // Get the number of peers with channels, but without funded ones. We don't care too much
                // about peers that never open a channel, so we filter by peers that have at least one
                // channel, and then limit the number of those with unfunded channels.
-               let channeled_peers_without_funding = self.peers_without_funded_channels(|node| !node.channel_by_id.is_empty());
+               let channeled_peers_without_funding =
+                       self.peers_without_funded_channels(|node| node.total_channel_count() > 0);
 
                let per_peer_state = self.per_peer_state.read().unwrap();
                let peer_state_mutex = per_peer_state.get(counterparty_node_id)
@@ -4730,7 +5111,7 @@ where
                // If this peer already has some channels, a new channel won't increase our number of peers
                // with unfunded channels, so as long as we aren't over the maximum number of unfunded
                // channels per-peer we can accept channels from a peer with existing ones.
-               if peer_state.channel_by_id.is_empty() &&
+               if peer_state.total_channel_count() == 0 &&
                        channeled_peers_without_funding >= MAX_UNFUNDED_CHANNEL_PEERS &&
                        !self.default_configuration.manually_accept_inbound_channels
                {
@@ -4746,7 +5127,7 @@ where
                                msg.temporary_channel_id.clone()));
                }
 
-               let mut channel = match Channel::new_from_req(&self.fee_estimator, &self.entropy_source, &self.signer_provider,
+               let mut channel = match InboundV1Channel::new(&self.fee_estimator, &self.entropy_source, &self.signer_provider,
                        counterparty_node_id.clone(), &self.channel_type_features(), &peer_state.latest_features, msg, user_channel_id,
                        &self.default_configuration, best_block_height, &self.logger, outbound_scid_alias)
                {
@@ -4756,33 +5137,35 @@ where
                        },
                        Ok(res) => res
                };
-               match peer_state.channel_by_id.entry(channel.channel_id()) {
-                       hash_map::Entry::Occupied(_) => {
-                               self.outbound_scid_aliases.lock().unwrap().remove(&outbound_scid_alias);
-                               return Err(MsgHandleErrInternal::send_err_msg_no_close("temporary_channel_id collision for the same peer!".to_owned(), msg.temporary_channel_id.clone()))
-                       },
-                       hash_map::Entry::Vacant(entry) => {
-                               if !self.default_configuration.manually_accept_inbound_channels {
-                                       if channel.get_channel_type().requires_zero_conf() {
-                                               return Err(MsgHandleErrInternal::send_err_msg_no_close("No zero confirmation channels accepted".to_owned(), msg.temporary_channel_id.clone()));
-                                       }
-                                       peer_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
-                                               node_id: counterparty_node_id.clone(),
-                                               msg: channel.accept_inbound_channel(user_channel_id),
-                                       });
-                               } else {
-                                       let mut pending_events = self.pending_events.lock().unwrap();
-                                       pending_events.push_back((events::Event::OpenChannelRequest {
-                                               temporary_channel_id: msg.temporary_channel_id.clone(),
-                                               counterparty_node_id: counterparty_node_id.clone(),
-                                               funding_satoshis: msg.funding_satoshis,
-                                               push_msat: msg.push_msat,
-                                               channel_type: channel.get_channel_type().clone(),
-                                       }, None));
+               let channel_id = channel.context.channel_id();
+               let channel_exists = peer_state.has_channel(&channel_id);
+               if channel_exists {
+                       self.outbound_scid_aliases.lock().unwrap().remove(&outbound_scid_alias);
+                       return Err(MsgHandleErrInternal::send_err_msg_no_close("temporary_channel_id collision for the same peer!".to_owned(), msg.temporary_channel_id.clone()))
+               } else {
+                       if !self.default_configuration.manually_accept_inbound_channels {
+                               let channel_type = channel.context.get_channel_type();
+                               if channel_type.requires_zero_conf() {
+                                       return Err(MsgHandleErrInternal::send_err_msg_no_close("No zero confirmation channels accepted".to_owned(), msg.temporary_channel_id.clone()));
                                }
-
-                               entry.insert(channel);
+                               if channel_type.requires_anchors_zero_fee_htlc_tx() {
+                                       return Err(MsgHandleErrInternal::send_err_msg_no_close("No channels with anchor outputs accepted".to_owned(), msg.temporary_channel_id.clone()));
+                               }
+                               peer_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
+                                       node_id: counterparty_node_id.clone(),
+                                       msg: channel.accept_inbound_channel(user_channel_id),
+                               });
+                       } else {
+                               let mut pending_events = self.pending_events.lock().unwrap();
+                               pending_events.push_back((events::Event::OpenChannelRequest {
+                                       temporary_channel_id: msg.temporary_channel_id.clone(),
+                                       counterparty_node_id: counterparty_node_id.clone(),
+                                       funding_satoshis: msg.funding_satoshis,
+                                       push_msat: msg.push_msat,
+                                       channel_type: channel.context.get_channel_type().clone(),
+                               }, None));
                        }
+                       peer_state.inbound_v1_channel_by_id.insert(channel_id, channel);
                }
                Ok(())
        }
@@ -4797,10 +5180,10 @@ where
                                })?;
                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                        let peer_state = &mut *peer_state_lock;
-                       match peer_state.channel_by_id.entry(msg.temporary_channel_id) {
+                       match peer_state.outbound_v1_channel_by_id.entry(msg.temporary_channel_id) {
                                hash_map::Entry::Occupied(mut chan) => {
-                                       try_chan_entry!(self, chan.get_mut().accept_channel(&msg, &self.default_configuration.channel_handshake_limits, &peer_state.latest_features), chan);
-                                       (chan.get().get_value_satoshis(), chan.get().get_funding_redeemscript().to_v0_p2wsh(), chan.get().get_user_id())
+                                       try_v1_outbound_chan_entry!(self, chan.get_mut().accept_channel(&msg, &self.default_configuration.channel_handshake_limits, &peer_state.latest_features), chan);
+                                       (chan.get().context.get_value_satoshis(), chan.get().context.get_funding_redeemscript().to_v0_p2wsh(), chan.get().context.get_user_id())
                                },
                                hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", counterparty_node_id), msg.temporary_channel_id))
                        }
@@ -4828,12 +5211,24 @@ where
 
                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                let peer_state = &mut *peer_state_lock;
-               let ((funding_msg, monitor), chan) =
-                       match peer_state.channel_by_id.entry(msg.temporary_channel_id) {
-                               hash_map::Entry::Occupied(mut chan) => {
-                                       (try_chan_entry!(self, chan.get_mut().funding_created(msg, best_block, &self.signer_provider, &self.logger), chan), chan.remove())
+               let (chan, funding_msg, monitor) =
+                       match peer_state.inbound_v1_channel_by_id.remove(&msg.temporary_channel_id) {
+                               Some(inbound_chan) => {
+                                       match inbound_chan.funding_created(msg, best_block, &self.signer_provider, &self.logger) {
+                                               Ok(res) => res,
+                                               Err((mut inbound_chan, err)) => {
+                                                       // We've already removed this inbound channel from the map in `PeerState`
+                                                       // above so at this point we just need to clean up any lingering entries
+                                                       // concerning this channel as it is safe to do so.
+                                                       update_maps_on_chan_removal!(self, &inbound_chan.context);
+                                                       let user_id = inbound_chan.context.get_user_id();
+                                                       let shutdown_res = inbound_chan.context.force_shutdown(false);
+                                                       return Err(MsgHandleErrInternal::from_finish_shutdown(format!("{}", err),
+                                                               msg.temporary_channel_id, user_id, shutdown_res, None));
+                                               },
+                                       }
                                },
-                               hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", counterparty_node_id), msg.temporary_channel_id))
+                               None => return Err(MsgHandleErrInternal::send_err_msg_no_close(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", counterparty_node_id), msg.temporary_channel_id))
                        };
 
                match peer_state.channel_by_id.entry(funding_msg.channel_id) {
@@ -4841,14 +5236,14 @@ where
                                Err(MsgHandleErrInternal::send_err_msg_no_close("Already had channel with the new channel_id".to_owned(), funding_msg.channel_id))
                        },
                        hash_map::Entry::Vacant(e) => {
-                               match self.id_to_peer.lock().unwrap().entry(chan.channel_id()) {
+                               match self.id_to_peer.lock().unwrap().entry(chan.context.channel_id()) {
                                        hash_map::Entry::Occupied(_) => {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close(
                                                        "The funding_created message had the same funding_txid as an existing channel - funding is not possible".to_owned(),
                                                        funding_msg.channel_id))
                                        },
                                        hash_map::Entry::Vacant(i_e) => {
-                                               i_e.insert(chan.get_counterparty_node_id());
+                                               i_e.insert(chan.context.get_counterparty_node_id());
                                        }
                                }
 
@@ -4865,8 +5260,9 @@ where
                                let monitor_res = self.chain_monitor.watch_channel(monitor.get_funding_txo().0, monitor);
 
                                let chan = e.insert(chan);
-                               let mut res = handle_new_monitor_update!(self, monitor_res, 0, peer_state_lock, peer_state,
-                                       per_peer_state, chan, MANUALLY_REMOVING, { peer_state.channel_by_id.remove(&new_channel_id) });
+                               let mut res = handle_new_monitor_update!(self, monitor_res, peer_state_lock, peer_state,
+                                       per_peer_state, chan, MANUALLY_REMOVING_INITIAL_MONITOR,
+                                       { peer_state.channel_by_id.remove(&new_channel_id) });
 
                                // Note that we reply with the new channel_id in error messages if we gave up on the
                                // channel, not the temporary_channel_id. This is compatible with ourselves, but the
@@ -4878,7 +5274,7 @@ where
                                if let Err(MsgHandleErrInternal { shutdown_finish: Some((res, _)), .. }) = &mut res {
                                        res.0 = None;
                                }
-                               res
+                               res.map(|_| ())
                        }
                }
        }
@@ -4898,8 +5294,8 @@ where
                        hash_map::Entry::Occupied(mut chan) => {
                                let monitor = try_chan_entry!(self,
                                        chan.get_mut().funding_signed(&msg, best_block, &self.signer_provider, &self.logger), chan);
-                               let update_res = self.chain_monitor.watch_channel(chan.get().get_funding_txo().unwrap(), monitor);
-                               let mut res = handle_new_monitor_update!(self, update_res, 0, peer_state_lock, peer_state, per_peer_state, chan);
+                               let update_res = self.chain_monitor.watch_channel(chan.get().context.get_funding_txo().unwrap(), monitor);
+                               let mut res = handle_new_monitor_update!(self, update_res, peer_state_lock, peer_state, per_peer_state, chan, INITIAL_MONITOR);
                                if let Err(MsgHandleErrInternal { ref mut shutdown_finish, .. }) = res {
                                        // We weren't able to watch the channel to begin with, so no updates should be made on
                                        // it. Previously, full_stack_target found an (unreachable) panic when the
@@ -4908,7 +5304,7 @@ where
                                                shutdown_finish.0.take();
                                        }
                                }
-                               res
+                               res.map(|_| ())
                        },
                        hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close("Failed to find corresponding channel".to_owned(), msg.channel_id))
                }
@@ -4928,18 +5324,18 @@ where
                                let announcement_sigs_opt = try_chan_entry!(self, chan.get_mut().channel_ready(&msg, &self.node_signer,
                                        self.genesis_hash.clone(), &self.default_configuration, &self.best_block.read().unwrap(), &self.logger), chan);
                                if let Some(announcement_sigs) = announcement_sigs_opt {
-                                       log_trace!(self.logger, "Sending announcement_signatures for channel {}", log_bytes!(chan.get().channel_id()));
+                                       log_trace!(self.logger, "Sending announcement_signatures for channel {}", log_bytes!(chan.get().context.channel_id()));
                                        peer_state.pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
                                                node_id: counterparty_node_id.clone(),
                                                msg: announcement_sigs,
                                        });
-                               } else if chan.get().is_usable() {
+                               } else if chan.get().context.is_usable() {
                                        // If we're sending an announcement_signatures, we'll send the (public)
                                        // channel_update after sending a channel_announcement when we receive our
                                        // counterparty's announcement_signatures. Thus, we only bother to send a
                                        // channel_update here if the channel is not public, i.e. we're not sending an
                                        // announcement_signatures.
-                                       log_trace!(self.logger, "Sending private initial channel_update for our counterparty on channel {}", log_bytes!(chan.get().channel_id()));
+                                       log_trace!(self.logger, "Sending private initial channel_update for our counterparty on channel {}", log_bytes!(chan.get().context.channel_id()));
                                        if let Ok(msg) = self.get_channel_update_for_unicast(chan.get()) {
                                                peer_state.pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
                                                        node_id: counterparty_node_id.clone(),
@@ -4979,7 +5375,7 @@ where
                                                        if chan_entry.get().sent_shutdown() { " after we initiated shutdown" } else { "" });
                                        }
 
-                                       let funding_txo_opt = chan_entry.get().get_funding_txo();
+                                       let funding_txo_opt = chan_entry.get().context.get_funding_txo();
                                        let (shutdown, monitor_update_opt, htlcs) = try_chan_entry!(self,
                                                chan_entry.get_mut().shutdown(&self.signer_provider, &peer_state.latest_features, &msg), chan_entry);
                                        dropped_htlcs = htlcs;
@@ -4996,9 +5392,8 @@ where
 
                                        // Update the monitor with the shutdown script if necessary.
                                        if let Some(monitor_update) = monitor_update_opt {
-                                               let update_id = monitor_update.update_id;
-                                               let update_res = self.chain_monitor.update_channel(funding_txo_opt.unwrap(), monitor_update);
-                                               break handle_new_monitor_update!(self, update_res, update_id, peer_state_lock, peer_state, per_peer_state, chan_entry);
+                                               break handle_new_monitor_update!(self, funding_txo_opt.unwrap(), monitor_update,
+                                                       peer_state_lock, peer_state, per_peer_state, chan_entry).map(|_| ());
                                        }
                                        break Ok(());
                                },
@@ -5057,7 +5452,7 @@ where
                                        msg: update
                                });
                        }
-                       self.issue_channel_close_events(&chan, ClosureReason::CooperativeClosure);
+                       self.issue_channel_close_events(&chan.context, ClosureReason::CooperativeClosure);
                }
                Ok(())
        }
@@ -5072,7 +5467,7 @@ where
                //encrypted with the same key. It's not immediately obvious how to usefully exploit that,
                //but we should prevent it anyway.
 
-               let pending_forward_info = self.decode_update_add_htlc_onion(msg);
+               let decoded_hop_res = self.decode_update_add_htlc_onion(msg);
                let per_peer_state = self.per_peer_state.read().unwrap();
                let peer_state_mutex = per_peer_state.get(counterparty_node_id)
                        .ok_or_else(|| {
@@ -5084,6 +5479,12 @@ where
                match peer_state.channel_by_id.entry(msg.channel_id) {
                        hash_map::Entry::Occupied(mut chan) => {
 
+                               let pending_forward_info = match decoded_hop_res {
+                                       Ok((next_hop, shared_secret, next_packet_pk_opt)) =>
+                                               self.construct_pending_htlc_status(msg, shared_secret, next_hop,
+                                                       chan.get().context.config().accept_underpaying_htlcs, next_packet_pk_opt),
+                                       Err(e) => PendingHTLCStatus::Fail(e)
+                               };
                                let create_pending_htlc_status = |chan: &Channel<<SP::Target as SignerProvider>::Signer>, pending_forward_info: PendingHTLCStatus, error_code: u16| {
                                        // If the update_add is completely bogus, the call will Err and we will close,
                                        // but if we've sent a shutdown and they haven't acknowledged it yet, we just
@@ -5185,13 +5586,11 @@ where
                let peer_state = &mut *peer_state_lock;
                match peer_state.channel_by_id.entry(msg.channel_id) {
                        hash_map::Entry::Occupied(mut chan) => {
-                               let funding_txo = chan.get().get_funding_txo();
+                               let funding_txo = chan.get().context.get_funding_txo();
                                let monitor_update_opt = try_chan_entry!(self, chan.get_mut().commitment_signed(&msg, &self.logger), chan);
                                if let Some(monitor_update) = monitor_update_opt {
-                                       let update_res = self.chain_monitor.update_channel(funding_txo.unwrap(), monitor_update);
-                                       let update_id = monitor_update.update_id;
-                                       handle_new_monitor_update!(self, update_res, update_id, peer_state_lock,
-                                               peer_state, per_peer_state, chan)
+                                       handle_new_monitor_update!(self, funding_txo.unwrap(), monitor_update, peer_state_lock,
+                                               peer_state, per_peer_state, chan).map(|_| ())
                                } else { Ok(()) }
                        },
                        hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", counterparty_node_id), msg.channel_id))
@@ -5295,6 +5694,24 @@ where
                }
        }
 
+       /// Checks whether [`ChannelMonitorUpdate`]s generated by the receipt of a remote
+       /// [`msgs::RevokeAndACK`] should be held for the given channel until some other event
+       /// completes. Note that this needs to happen in the same [`PeerState`] mutex as any release of
+       /// the [`ChannelMonitorUpdate`] in question.
+       fn raa_monitor_updates_held(&self,
+               actions_blocking_raa_monitor_updates: &BTreeMap<[u8; 32], Vec<RAAMonitorUpdateBlockingAction>>,
+               channel_funding_outpoint: OutPoint, counterparty_node_id: PublicKey
+       ) -> bool {
+               actions_blocking_raa_monitor_updates
+                       .get(&channel_funding_outpoint.to_channel_id()).map(|v| !v.is_empty()).unwrap_or(false)
+               || self.pending_events.lock().unwrap().iter().any(|(_, action)| {
+                       action == &Some(EventCompletionAction::ReleaseRAAChannelMonitorUpdate {
+                               channel_funding_outpoint,
+                               counterparty_node_id,
+                       })
+               })
+       }
+
        fn internal_revoke_and_ack(&self, counterparty_node_id: &PublicKey, msg: &msgs::RevokeAndACK) -> Result<(), MsgHandleErrInternal> {
                let (htlcs_to_fail, res) = {
                        let per_peer_state = self.per_peer_state.read().unwrap();
@@ -5306,13 +5723,11 @@ where
                        let peer_state = &mut *peer_state_lock;
                        match peer_state.channel_by_id.entry(msg.channel_id) {
                                hash_map::Entry::Occupied(mut chan) => {
-                                       let funding_txo = chan.get().get_funding_txo();
+                                       let funding_txo = chan.get().context.get_funding_txo();
                                        let (htlcs_to_fail, monitor_update_opt) = try_chan_entry!(self, chan.get_mut().revoke_and_ack(&msg, &self.logger), chan);
                                        let res = if let Some(monitor_update) = monitor_update_opt {
-                                               let update_res = self.chain_monitor.update_channel(funding_txo.unwrap(), monitor_update);
-                                               let update_id = monitor_update.update_id;
-                                               handle_new_monitor_update!(self, update_res, update_id,
-                                                       peer_state_lock, peer_state, per_peer_state, chan)
+                                               handle_new_monitor_update!(self, funding_txo.unwrap(), monitor_update,
+                                                       peer_state_lock, peer_state, per_peer_state, chan).map(|_| ())
                                        } else { Ok(()) };
                                        (htlcs_to_fail, res)
                                },
@@ -5352,7 +5767,7 @@ where
                let peer_state = &mut *peer_state_lock;
                match peer_state.channel_by_id.entry(msg.channel_id) {
                        hash_map::Entry::Occupied(mut chan) => {
-                               if !chan.get().is_usable() {
+                               if !chan.get().context.is_usable() {
                                        return Err(MsgHandleErrInternal::from_no_close(LightningError{err: "Got an announcement_signatures before we were ready for it".to_owned(), action: msgs::ErrorAction::IgnoreError}));
                                }
 
@@ -5389,8 +5804,8 @@ where
                let peer_state = &mut *peer_state_lock;
                match peer_state.channel_by_id.entry(chan_id) {
                        hash_map::Entry::Occupied(mut chan) => {
-                               if chan.get().get_counterparty_node_id() != *counterparty_node_id {
-                                       if chan.get().should_announce() {
+                               if chan.get().context.get_counterparty_node_id() != *counterparty_node_id {
+                                       if chan.get().context.should_announce() {
                                                // If the announcement is about a channel of ours which is public, some
                                                // other peer may simply be forwarding all its gossip to us. Don't provide
                                                // a scary-looking error message and return Ok instead.
@@ -5398,7 +5813,7 @@ where
                                        }
                                        return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a channel_update for a channel from the wrong node - it shouldn't know about our private channels!".to_owned(), chan_id));
                                }
-                               let were_node_one = self.get_our_node_id().serialize()[..] < chan.get().get_counterparty_node_id().serialize()[..];
+                               let were_node_one = self.get_our_node_id().serialize()[..] < chan.get().context.get_counterparty_node_id().serialize()[..];
                                let msg_from_node_one = msg.contents.flags & 1 == 0;
                                if were_node_one == msg_from_node_one {
                                        return Ok(NotifyOption::SkipPersist);
@@ -5439,18 +5854,18 @@ where
                                                        node_id: counterparty_node_id.clone(),
                                                        msg,
                                                });
-                                       } else if chan.get().is_usable() {
+                                       } else if chan.get().context.is_usable() {
                                                // If the channel is in a usable state (ie the channel is not being shut
                                                // down), send a unicast channel_update to our counterparty to make sure
                                                // they have the latest channel parameters.
                                                if let Ok(msg) = self.get_channel_update_for_unicast(chan.get()) {
                                                        channel_update = Some(events::MessageSendEvent::SendChannelUpdate {
-                                                               node_id: chan.get().get_counterparty_node_id(),
+                                                               node_id: chan.get().context.get_counterparty_node_id(),
                                                                msg,
                                                        });
                                                }
                                        }
-                                       let need_lnd_workaround = chan.get_mut().workaround_lnd_bug_4006.take();
+                                       let need_lnd_workaround = chan.get_mut().context.workaround_lnd_bug_4006.take();
                                        htlc_forwards = self.handle_channel_resumption(
                                                &mut peer_state.pending_msg_events, chan.get_mut(), responses.raa, responses.commitment_update, responses.order,
                                                Vec::new(), None, responses.channel_ready, responses.announcement_sigs);
@@ -5513,7 +5928,7 @@ where
                                                                let pending_msg_events = &mut peer_state.pending_msg_events;
                                                                if let hash_map::Entry::Occupied(chan_entry) = peer_state.channel_by_id.entry(funding_outpoint.to_channel_id()) {
                                                                        let mut chan = remove_channel!(self, chan_entry);
-                                                                       failed_channels.push(chan.force_shutdown(false));
+                                                                       failed_channels.push(chan.context.force_shutdown(false));
                                                                        if let Ok(update) = self.get_channel_update_for_broadcast(&chan) {
                                                                                pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                                                        msg: update
@@ -5524,11 +5939,11 @@ where
                                                                        } else {
                                                                                ClosureReason::CommitmentTxConfirmed
                                                                        };
-                                                                       self.issue_channel_close_events(&chan, reason);
+                                                                       self.issue_channel_close_events(&chan.context, reason);
                                                                        pending_msg_events.push(events::MessageSendEvent::HandleError {
-                                                                               node_id: chan.get_counterparty_node_id(),
+                                                                               node_id: chan.context.get_counterparty_node_id(),
                                                                                action: msgs::ErrorAction::SendErrorMessage {
-                                                                                       msg: msgs::ErrorMessage { channel_id: chan.channel_id(), data: "Channel force-closed".to_owned() }
+                                                                                       msg: msgs::ErrorMessage { channel_id: chan.context.channel_id(), data: "Channel force-closed".to_owned() }
                                                                                },
                                                                        });
                                                                }
@@ -5554,13 +5969,8 @@ where
        /// update events as a separate process method here.
        #[cfg(fuzzing)]
        pub fn process_monitor_events(&self) {
-               PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock, &self.persistence_notifier, || {
-                       if self.process_pending_monitor_events() {
-                               NotifyOption::DoPersist
-                       } else {
-                               NotifyOption::SkipPersist
-                       }
-               });
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
+               self.process_pending_monitor_events();
        }
 
        /// Check the holding cell in each channel and free any pending HTLCs in them if possible.
@@ -5582,8 +5992,8 @@ where
                                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                                        let peer_state: &mut PeerState<_> = &mut *peer_state_lock;
                                        for (channel_id, chan) in peer_state.channel_by_id.iter_mut() {
-                                               let counterparty_node_id = chan.get_counterparty_node_id();
-                                               let funding_txo = chan.get_funding_txo();
+                                               let counterparty_node_id = chan.context.get_counterparty_node_id();
+                                               let funding_txo = chan.context.get_funding_txo();
                                                let (monitor_opt, holding_cell_failed_htlcs) =
                                                        chan.maybe_free_holding_cell_htlcs(&self.logger);
                                                if !holding_cell_failed_htlcs.is_empty() {
@@ -5592,11 +6002,8 @@ where
                                                if let Some(monitor_update) = monitor_opt {
                                                        has_monitor_update = true;
 
-                                                       let update_res = self.chain_monitor.update_channel(
-                                                               funding_txo.expect("channel is live"), monitor_update);
-                                                       let update_id = monitor_update.update_id;
                                                        let channel_id: [u8; 32] = *channel_id;
-                                                       let res = handle_new_monitor_update!(self, update_res, update_id,
+                                                       let res = handle_new_monitor_update!(self, funding_txo.unwrap(), monitor_update,
                                                                peer_state_lock, peer_state, per_peer_state, chan, MANUALLY_REMOVING,
                                                                peer_state.channel_by_id.remove(&channel_id));
                                                        if res.is_err() {
@@ -5642,7 +6049,7 @@ where
                                                        if let Some(msg) = msg_opt {
                                                                has_update = true;
                                                                pending_msg_events.push(events::MessageSendEvent::SendClosingSigned {
-                                                                       node_id: chan.get_counterparty_node_id(), msg,
+                                                                       node_id: chan.context.get_counterparty_node_id(), msg,
                                                                });
                                                        }
                                                        if let Some(tx) = tx_opt {
@@ -5654,18 +6061,18 @@ where
                                                                        });
                                                                }
 
-                                                               self.issue_channel_close_events(chan, ClosureReason::CooperativeClosure);
+                                                               self.issue_channel_close_events(&chan.context, ClosureReason::CooperativeClosure);
 
                                                                log_info!(self.logger, "Broadcasting {}", log_tx!(tx));
                                                                self.tx_broadcaster.broadcast_transactions(&[&tx]);
-                                                               update_maps_on_chan_removal!(self, chan);
+                                                               update_maps_on_chan_removal!(self, &chan.context);
                                                                false
                                                        } else { true }
                                                },
                                                Err(e) => {
                                                        has_update = true;
                                                        let (close_channel, res) = convert_chan_err!(self, e, chan, channel_id);
-                                                       handle_errors.push((chan.get_counterparty_node_id(), Err(res)));
+                                                       handle_errors.push((chan.context.get_counterparty_node_id(), Err(res)));
                                                        !close_channel
                                                }
                                        }
@@ -5692,48 +6099,20 @@ where
                        // Channel::force_shutdown tries to make us do) as we may still be in initialization,
                        // so we track the update internally and handle it when the user next calls
                        // timer_tick_occurred, guaranteeing we're running normally.
-                       if let Some((funding_txo, update)) = failure.0.take() {
+                       if let Some((counterparty_node_id, funding_txo, update)) = failure.0.take() {
                                assert_eq!(update.updates.len(), 1);
                                if let ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast } = update.updates[0] {
                                        assert!(should_broadcast);
                                } else { unreachable!(); }
-                               self.pending_background_events.lock().unwrap().push(BackgroundEvent::MonitorUpdateRegeneratedOnStartup((funding_txo, update)));
+                               self.pending_background_events.lock().unwrap().push(
+                                       BackgroundEvent::MonitorUpdateRegeneratedOnStartup {
+                                               counterparty_node_id, funding_txo, update
+                                       });
                        }
                        self.finish_force_close_channel(failure);
                }
        }
 
-       fn set_payment_hash_secret_map(&self, payment_hash: PaymentHash, payment_preimage: Option<PaymentPreimage>, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32) -> Result<PaymentSecret, APIError> {
-               assert!(invoice_expiry_delta_secs <= 60*60*24*365); // Sadly bitcoin timestamps are u32s, so panic before 2106
-
-               if min_value_msat.is_some() && min_value_msat.unwrap() > MAX_VALUE_MSAT {
-                       return Err(APIError::APIMisuseError { err: format!("min_value_msat of {} greater than total 21 million bitcoin supply", min_value_msat.unwrap()) });
-               }
-
-               let payment_secret = PaymentSecret(self.entropy_source.get_secure_random_bytes());
-
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
-               let mut payment_secrets = self.pending_inbound_payments.lock().unwrap();
-               match payment_secrets.entry(payment_hash) {
-                       hash_map::Entry::Vacant(e) => {
-                               e.insert(PendingInboundPayment {
-                                       payment_secret, min_value_msat, payment_preimage,
-                                       user_payment_id: 0, // For compatibility with version 0.0.103 and earlier
-                                       // We assume that highest_seen_timestamp is pretty close to the current time -
-                                       // it's updated when we receive a new block with the maximum time we've seen in
-                                       // a header. It should never be more than two hours in the future.
-                                       // Thus, we add two hours here as a buffer to ensure we absolutely
-                                       // never fail a payment too early.
-                                       // Note that we assume that received blocks have reasonably up-to-date
-                                       // timestamps.
-                                       expiry_time: self.highest_seen_timestamp.load(Ordering::Acquire) as u64 + invoice_expiry_delta_secs as u64 + 7200,
-                               });
-                       },
-                       hash_map::Entry::Occupied(_) => return Err(APIError::APIMisuseError { err: "Duplicate payment hash".to_owned() }),
-               }
-               Ok(payment_secret)
-       }
-
        /// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
        /// to pay us.
        ///
@@ -5773,23 +6152,6 @@ where
                        min_final_cltv_expiry_delta)
        }
 
-       /// Legacy version of [`create_inbound_payment`]. Use this method if you wish to share
-       /// serialized state with LDK node(s) running 0.0.103 and earlier.
-       ///
-       /// May panic if `invoice_expiry_delta_secs` is greater than one year.
-       ///
-       /// # Note
-       /// This method is deprecated and will be removed soon.
-       ///
-       /// [`create_inbound_payment`]: Self::create_inbound_payment
-       #[deprecated]
-       pub fn create_inbound_payment_legacy(&self, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32) -> Result<(PaymentHash, PaymentSecret), APIError> {
-               let payment_preimage = PaymentPreimage(self.entropy_source.get_secure_random_bytes());
-               let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
-               let payment_secret = self.set_payment_hash_secret_map(payment_hash, Some(payment_preimage), min_value_msat, invoice_expiry_delta_secs)?;
-               Ok((payment_hash, payment_secret))
-       }
-
        /// Gets a [`PaymentSecret`] for a given [`PaymentHash`], for which the payment preimage is
        /// stored external to LDK.
        ///
@@ -5843,20 +6205,6 @@ where
                        min_final_cltv_expiry)
        }
 
-       /// Legacy version of [`create_inbound_payment_for_hash`]. Use this method if you wish to share
-       /// serialized state with LDK node(s) running 0.0.103 and earlier.
-       ///
-       /// May panic if `invoice_expiry_delta_secs` is greater than one year.
-       ///
-       /// # Note
-       /// This method is deprecated and will be removed soon.
-       ///
-       /// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash
-       #[deprecated]
-       pub fn create_inbound_payment_for_hash_legacy(&self, payment_hash: PaymentHash, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32) -> Result<PaymentSecret, APIError> {
-               self.set_payment_hash_secret_map(payment_hash, None, min_value_msat, invoice_expiry_delta_secs)
-       }
-
        /// Gets an LDK-generated payment preimage from a payment hash and payment secret that were
        /// previously returned from [`create_inbound_payment`].
        ///
@@ -5931,7 +6279,7 @@ where
                inflight_htlcs
        }
 
-       #[cfg(any(test, fuzzing, feature = "_test_utils"))]
+       #[cfg(any(test, feature = "_test_utils"))]
        pub fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
                let events = core::cell::RefCell::new(Vec::new());
                let event_handler = |event: events::Event| events.borrow_mut().push(event);
@@ -5961,33 +6309,43 @@ where
                self.pending_outbound_payments.clear_pending_payments()
        }
 
-       fn handle_monitor_update_release(&self, counterparty_node_id: PublicKey, channel_funding_outpoint: OutPoint) {
+       /// When something which was blocking a channel from updating its [`ChannelMonitor`] (e.g. an
+       /// [`Event`] being handled) completes, this should be called to restore the channel to normal
+       /// operation. It will double-check that nothing *else* is also blocking the same channel from
+       /// making progress and then any blocked [`ChannelMonitorUpdate`]s fly.
+       fn handle_monitor_update_release(&self, counterparty_node_id: PublicKey, channel_funding_outpoint: OutPoint, mut completed_blocker: Option<RAAMonitorUpdateBlockingAction>) {
                let mut errors = Vec::new();
                loop {
                        let per_peer_state = self.per_peer_state.read().unwrap();
                        if let Some(peer_state_mtx) = per_peer_state.get(&counterparty_node_id) {
                                let mut peer_state_lck = peer_state_mtx.lock().unwrap();
                                let peer_state = &mut *peer_state_lck;
-                               if self.pending_events.lock().unwrap().iter()
-                                       .any(|(_ev, action_opt)| action_opt == &Some(EventCompletionAction::ReleaseRAAChannelMonitorUpdate {
-                                               channel_funding_outpoint, counterparty_node_id
-                                       }))
-                               {
-                                       // Check that, while holding the peer lock, we don't have another event
-                                       // blocking any monitor updates for this channel. If we do, let those
-                                       // events be the ones that ultimately release the monitor update(s).
-                                       log_trace!(self.logger, "Delaying monitor unlock for channel {} as another event is pending",
+
+                               if let Some(blocker) = completed_blocker.take() {
+                                       // Only do this on the first iteration of the loop.
+                                       if let Some(blockers) = peer_state.actions_blocking_raa_monitor_updates
+                                               .get_mut(&channel_funding_outpoint.to_channel_id())
+                                       {
+                                               blockers.retain(|iter| iter != &blocker);
+                                       }
+                               }
+
+                               if self.raa_monitor_updates_held(&peer_state.actions_blocking_raa_monitor_updates,
+                                       channel_funding_outpoint, counterparty_node_id) {
+                                       // Check that, while holding the peer lock, we don't have anything else
+                                       // blocking monitor updates for this channel. If we do, release the monitor
+                                       // update(s) when those blockers complete.
+                                       log_trace!(self.logger, "Delaying monitor unlock for channel {} as another channel's mon update needs to complete first",
                                                log_bytes!(&channel_funding_outpoint.to_channel_id()[..]));
                                        break;
                                }
+
                                if let hash_map::Entry::Occupied(mut chan) = peer_state.channel_by_id.entry(channel_funding_outpoint.to_channel_id()) {
-                                       debug_assert_eq!(chan.get().get_funding_txo().unwrap(), channel_funding_outpoint);
+                                       debug_assert_eq!(chan.get().context.get_funding_txo().unwrap(), channel_funding_outpoint);
                                        if let Some((monitor_update, further_update_exists)) = chan.get_mut().unblock_next_blocked_monitor_update() {
                                                log_debug!(self.logger, "Unlocking monitor updating for channel {} and updating monitor",
                                                        log_bytes!(&channel_funding_outpoint.to_channel_id()[..]));
-                                               let update_res = self.chain_monitor.update_channel(channel_funding_outpoint, monitor_update);
-                                               let update_id = monitor_update.update_id;
-                                               if let Err(e) = handle_new_monitor_update!(self, update_res, update_id,
+                                               if let Err(e) = handle_new_monitor_update!(self, channel_funding_outpoint, monitor_update,
                                                        peer_state_lck, peer_state, per_peer_state, chan)
                                                {
                                                        errors.push((e, counterparty_node_id));
@@ -6021,7 +6379,7 @@ where
                                EventCompletionAction::ReleaseRAAChannelMonitorUpdate {
                                        channel_funding_outpoint, counterparty_node_id
                                } => {
-                                       self.handle_monitor_update_release(counterparty_node_id, channel_funding_outpoint);
+                                       self.handle_monitor_update_release(counterparty_node_id, channel_funding_outpoint, None);
                                }
                        }
                }
@@ -6066,7 +6424,7 @@ where
        fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent> {
                let events = RefCell::new(Vec::new());
                PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock, &self.persistence_notifier, || {
-                       let mut result = NotifyOption::SkipPersist;
+                       let mut result = self.process_background_events();
 
                        // TODO: This behavior should be documented. It's unintuitive that we query
                        // ChannelMonitors when clearing other events.
@@ -6147,7 +6505,8 @@ where
        }
 
        fn block_disconnected(&self, header: &BlockHeader, height: u32) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock,
+                       &self.persistence_notifier, || -> NotifyOption { NotifyOption::DoPersist });
                let new_height = height - 1;
                {
                        let mut best_block = self.best_block.write().unwrap();
@@ -6181,7 +6540,8 @@ where
                let block_hash = header.block_hash();
                log_trace!(self.logger, "{} transactions included in block {} at height {} provided", txdata.len(), block_hash, height);
 
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock,
+                       &self.persistence_notifier, || -> NotifyOption { NotifyOption::DoPersist });
                self.do_chain_event(Some(height), |channel| channel.transactions_confirmed(&block_hash, height, txdata, self.genesis_hash.clone(), &self.node_signer, &self.default_configuration, &self.logger)
                        .map(|(a, b)| (a, Vec::new(), b)));
 
@@ -6200,8 +6560,8 @@ where
                let block_hash = header.block_hash();
                log_trace!(self.logger, "New best block: {} at height {}", block_hash, height);
 
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
-
+               let _persistence_guard = PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock,
+                       &self.persistence_notifier, || -> NotifyOption { NotifyOption::DoPersist });
                *self.best_block.write().unwrap() = BestBlock::new(block_hash, height);
 
                self.do_chain_event(Some(height), |channel| channel.best_block_updated(height, header.time, self.genesis_hash.clone(), &self.node_signer, &self.default_configuration, &self.logger));
@@ -6235,7 +6595,7 @@ where
                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                        let peer_state = &mut *peer_state_lock;
                        for chan in peer_state.channel_by_id.values() {
-                               if let (Some(funding_txo), Some(block_hash)) = (chan.get_funding_txo(), chan.get_funding_tx_confirmed_in()) {
+                               if let (Some(funding_txo), Some(block_hash)) = (chan.context.get_funding_txo(), chan.context.get_funding_tx_confirmed_in()) {
                                        res.push((funding_txo.txid, Some(block_hash)));
                                }
                        }
@@ -6244,9 +6604,10 @@ where
        }
 
        fn transaction_unconfirmed(&self, txid: &Txid) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock,
+                       &self.persistence_notifier, || -> NotifyOption { NotifyOption::DoPersist });
                self.do_chain_event(None, |channel| {
-                       if let Some(funding_txo) = channel.get_funding_txo() {
+                       if let Some(funding_txo) = channel.context.get_funding_txo() {
                                if funding_txo.txid == *txid {
                                        channel.funding_transaction_unconfirmed(&self.logger).map(|()| (None, Vec::new(), None))
                                } else { Ok((None, Vec::new(), None)) }
@@ -6289,20 +6650,20 @@ where
                                                for (source, payment_hash) in timed_out_pending_htlcs.drain(..) {
                                                        let (failure_code, data) = self.get_htlc_inbound_temp_fail_err_and_data(0x1000|14 /* expiry_too_soon */, &channel);
                                                        timed_out_htlcs.push((source, payment_hash, HTLCFailReason::reason(failure_code, data),
-                                                               HTLCDestination::NextHopChannel { node_id: Some(channel.get_counterparty_node_id()), channel_id: channel.channel_id() }));
+                                                               HTLCDestination::NextHopChannel { node_id: Some(channel.context.get_counterparty_node_id()), channel_id: channel.context.channel_id() }));
                                                }
                                                if let Some(channel_ready) = channel_ready_opt {
                                                        send_channel_ready!(self, pending_msg_events, channel, channel_ready);
-                                                       if channel.is_usable() {
-                                                               log_trace!(self.logger, "Sending channel_ready with private initial channel_update for our counterparty on channel {}", log_bytes!(channel.channel_id()));
+                                                       if channel.context.is_usable() {
+                                                               log_trace!(self.logger, "Sending channel_ready with private initial channel_update for our counterparty on channel {}", log_bytes!(channel.context.channel_id()));
                                                                if let Ok(msg) = self.get_channel_update_for_unicast(channel) {
                                                                        pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
-                                                                               node_id: channel.get_counterparty_node_id(),
+                                                                               node_id: channel.context.get_counterparty_node_id(),
                                                                                msg,
                                                                        });
                                                                }
                                                        } else {
-                                                               log_trace!(self.logger, "Sending channel_ready WITHOUT channel_update for {}", log_bytes!(channel.channel_id()));
+                                                               log_trace!(self.logger, "Sending channel_ready WITHOUT channel_update for {}", log_bytes!(channel.context.channel_id()));
                                                        }
                                                }
 
@@ -6312,9 +6673,9 @@ where
                                                }
 
                                                if let Some(announcement_sigs) = announcement_sigs {
-                                                       log_trace!(self.logger, "Sending announcement_signatures for channel {}", log_bytes!(channel.channel_id()));
+                                                       log_trace!(self.logger, "Sending announcement_signatures for channel {}", log_bytes!(channel.context.channel_id()));
                                                        pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
-                                                               node_id: channel.get_counterparty_node_id(),
+                                                               node_id: channel.context.get_counterparty_node_id(),
                                                                msg: announcement_sigs,
                                                        });
                                                        if let Some(height) = height_opt {
@@ -6329,7 +6690,7 @@ where
                                                        }
                                                }
                                                if channel.is_our_channel_ready() {
-                                                       if let Some(real_scid) = channel.get_short_channel_id() {
+                                                       if let Some(real_scid) = channel.context.get_short_channel_id() {
                                                                // If we sent a 0conf channel_ready, and now have an SCID, we add it
                                                                // to the short_to_chan_info map here. Note that we check whether we
                                                                // can relay using the real SCID at relay-time (i.e.
@@ -6337,28 +6698,28 @@ where
                                                                // un-confirmed we force-close the channel, ensuring short_to_chan_info
                                                                // is always consistent.
                                                                let mut short_to_chan_info = self.short_to_chan_info.write().unwrap();
-                                                               let scid_insert = short_to_chan_info.insert(real_scid, (channel.get_counterparty_node_id(), channel.channel_id()));
-                                                               assert!(scid_insert.is_none() || scid_insert.unwrap() == (channel.get_counterparty_node_id(), channel.channel_id()),
+                                                               let scid_insert = short_to_chan_info.insert(real_scid, (channel.context.get_counterparty_node_id(), channel.context.channel_id()));
+                                                               assert!(scid_insert.is_none() || scid_insert.unwrap() == (channel.context.get_counterparty_node_id(), channel.context.channel_id()),
                                                                        "SCIDs should never collide - ensure you weren't behind by a full {} blocks when creating channels",
                                                                        fake_scid::MAX_SCID_BLOCKS_FROM_NOW);
                                                        }
                                                }
                                        } else if let Err(reason) = res {
-                                               update_maps_on_chan_removal!(self, channel);
+                                               update_maps_on_chan_removal!(self, &channel.context);
                                                // It looks like our counterparty went on-chain or funding transaction was
                                                // reorged out of the main chain. Close the channel.
-                                               failed_channels.push(channel.force_shutdown(true));
+                                               failed_channels.push(channel.context.force_shutdown(true));
                                                if let Ok(update) = self.get_channel_update_for_broadcast(&channel) {
                                                        pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                                msg: update
                                                        });
                                                }
                                                let reason_message = format!("{}", reason);
-                                               self.issue_channel_close_events(channel, reason);
+                                               self.issue_channel_close_events(&channel.context, reason);
                                                pending_msg_events.push(events::MessageSendEvent::HandleError {
-                                                       node_id: channel.get_counterparty_node_id(),
+                                                       node_id: channel.context.get_counterparty_node_id(),
                                                        action: msgs::ErrorAction::SendErrorMessage { msg: msgs::ErrorMessage {
-                                                               channel_id: channel.channel_id(),
+                                                               channel_id: channel.context.channel_id(),
                                                                data: reason_message,
                                                        } },
                                                });
@@ -6488,7 +6849,7 @@ where
        L::Target: Logger,
 {
        fn handle_open_channel(&self, counterparty_node_id: &PublicKey, msg: &msgs::OpenChannel) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_open_channel(counterparty_node_id, msg), *counterparty_node_id);
        }
 
@@ -6499,7 +6860,7 @@ where
        }
 
        fn handle_accept_channel(&self, counterparty_node_id: &PublicKey, msg: &msgs::AcceptChannel) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_accept_channel(counterparty_node_id, msg), *counterparty_node_id);
        }
 
@@ -6510,74 +6871,75 @@ where
        }
 
        fn handle_funding_created(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingCreated) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_funding_created(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_funding_signed(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingSigned) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_funding_signed(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_channel_ready(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReady) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_channel_ready(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_shutdown(&self, counterparty_node_id: &PublicKey, msg: &msgs::Shutdown) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_shutdown(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_closing_signed(&self, counterparty_node_id: &PublicKey, msg: &msgs::ClosingSigned) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_closing_signed(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_update_add_htlc(&self, counterparty_node_id: &PublicKey, msg: &msgs::UpdateAddHTLC) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_update_add_htlc(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_update_fulfill_htlc(&self, counterparty_node_id: &PublicKey, msg: &msgs::UpdateFulfillHTLC) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_update_fulfill_htlc(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_update_fail_htlc(&self, counterparty_node_id: &PublicKey, msg: &msgs::UpdateFailHTLC) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_update_fail_htlc(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_update_fail_malformed_htlc(&self, counterparty_node_id: &PublicKey, msg: &msgs::UpdateFailMalformedHTLC) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_update_fail_malformed_htlc(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_commitment_signed(&self, counterparty_node_id: &PublicKey, msg: &msgs::CommitmentSigned) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_commitment_signed(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_revoke_and_ack(&self, counterparty_node_id: &PublicKey, msg: &msgs::RevokeAndACK) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_revoke_and_ack(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_update_fee(&self, counterparty_node_id: &PublicKey, msg: &msgs::UpdateFee) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_update_fee(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_announcement_signatures(&self, counterparty_node_id: &PublicKey, msg: &msgs::AnnouncementSignatures) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_announcement_signatures(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn handle_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) {
                PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock, &self.persistence_notifier, || {
+                       let force_persist = self.process_background_events();
                        if let Ok(persist) = handle_error!(self, self.internal_channel_update(counterparty_node_id, msg), *counterparty_node_id) {
-                               persist
+                               if force_persist == NotifyOption::DoPersist { NotifyOption::DoPersist } else { persist }
                        } else {
                                NotifyOption::SkipPersist
                        }
@@ -6585,12 +6947,12 @@ where
        }
 
        fn handle_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let _ = handle_error!(self, self.internal_channel_reestablish(counterparty_node_id, msg), *counterparty_node_id);
        }
 
        fn peer_disconnected(&self, counterparty_node_id: &PublicKey) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                let mut failed_channels = Vec::new();
                let mut per_peer_state = self.per_peer_state.write().unwrap();
                let remove_peer = {
@@ -6603,12 +6965,22 @@ where
                                peer_state.channel_by_id.retain(|_, chan| {
                                        chan.remove_uncommitted_htlcs_and_mark_paused(&self.logger);
                                        if chan.is_shutdown() {
-                                               update_maps_on_chan_removal!(self, chan);
-                                               self.issue_channel_close_events(chan, ClosureReason::DisconnectedPeer);
+                                               update_maps_on_chan_removal!(self, &chan.context);
+                                               self.issue_channel_close_events(&chan.context, ClosureReason::DisconnectedPeer);
                                                return false;
                                        }
                                        true
                                });
+                               peer_state.inbound_v1_channel_by_id.retain(|_, chan| {
+                                       update_maps_on_chan_removal!(self, &chan.context);
+                                       self.issue_channel_close_events(&chan.context, ClosureReason::DisconnectedPeer);
+                                       false
+                               });
+                               peer_state.outbound_v1_channel_by_id.retain(|_, chan| {
+                                       update_maps_on_chan_removal!(self, &chan.context);
+                                       self.issue_channel_close_events(&chan.context, ClosureReason::DisconnectedPeer);
+                                       false
+                               });
                                pending_msg_events.retain(|msg| {
                                        match msg {
                                                // V1 Channel Establishment
@@ -6672,7 +7044,7 @@ where
                        return Err(());
                }
 
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                // If we have too many peers connected which don't have funded channels, disconnect the
                // peer immediately (as long as it doesn't have funded channels). If we have a bunch of
@@ -6690,9 +7062,13 @@ where
                                        }
                                        e.insert(Mutex::new(PeerState {
                                                channel_by_id: HashMap::new(),
+                                               outbound_v1_channel_by_id: HashMap::new(),
+                                               inbound_v1_channel_by_id: HashMap::new(),
                                                latest_features: init_msg.features.clone(),
                                                pending_msg_events: Vec::new(),
+                                               in_flight_monitor_updates: BTreeMap::new(),
                                                monitor_update_blocked_actions: BTreeMap::new(),
+                                               actions_blocking_raa_monitor_updates: BTreeMap::new(),
                                                is_connected: true,
                                        }));
                                },
@@ -6722,8 +7098,8 @@ where
                        let peer_state = &mut *peer_state_lock;
                        let pending_msg_events = &mut peer_state.pending_msg_events;
                        peer_state.channel_by_id.retain(|_, chan| {
-                               let retain = if chan.get_counterparty_node_id() == *counterparty_node_id {
-                                       if !chan.have_received_message() {
+                               let retain = if chan.context.get_counterparty_node_id() == *counterparty_node_id {
+                                       if !chan.context.have_received_message() {
                                                // If we created this (outbound) channel while we were disconnected from the
                                                // peer we probably failed to send the open_channel message, which is now
                                                // lost. We can't have had anything pending related to this channel, so we just
@@ -6731,13 +7107,13 @@ where
                                                false
                                        } else {
                                                pending_msg_events.push(events::MessageSendEvent::SendChannelReestablish {
-                                                       node_id: chan.get_counterparty_node_id(),
+                                                       node_id: chan.context.get_counterparty_node_id(),
                                                        msg: chan.get_channel_reestablish(&self.logger),
                                                });
                                                true
                                        }
                                } else { true };
-                               if retain && chan.get_counterparty_node_id() != *counterparty_node_id {
+                               if retain && chan.context.get_counterparty_node_id() != *counterparty_node_id {
                                        if let Some(msg) = chan.get_signed_channel_announcement(&self.node_signer, self.genesis_hash.clone(), self.best_block.read().unwrap().height(), &self.default_configuration) {
                                                if let Ok(update_msg) = self.get_channel_update_for_broadcast(chan) {
                                                        pending_msg_events.push(events::MessageSendEvent::SendChannelAnnouncement {
@@ -6755,7 +7131,7 @@ where
        }
 
        fn handle_error(&self, counterparty_node_id: &PublicKey, msg: &msgs::ErrorMessage) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                if msg.channel_id == [0; 32] {
                        let channel_ids: Vec<[u8; 32]> = {
@@ -6764,7 +7140,9 @@ where
                                if peer_state_mutex_opt.is_none() { return; }
                                let mut peer_state_lock = peer_state_mutex_opt.unwrap().lock().unwrap();
                                let peer_state = &mut *peer_state_lock;
-                               peer_state.channel_by_id.keys().cloned().collect()
+                               peer_state.channel_by_id.keys().cloned()
+                                       .chain(peer_state.outbound_v1_channel_by_id.keys().cloned())
+                                       .chain(peer_state.inbound_v1_channel_by_id.keys().cloned()).collect()
                        };
                        for channel_id in channel_ids {
                                // Untrusted messages from peer, we throw away the error if id points to a non-existent channel
@@ -6778,7 +7156,7 @@ where
                                if peer_state_mutex_opt.is_none() { return; }
                                let mut peer_state_lock = peer_state_mutex_opt.unwrap().lock().unwrap();
                                let peer_state = &mut *peer_state_lock;
-                               if let Some(chan) = peer_state.channel_by_id.get_mut(&msg.channel_id) {
+                               if let Some(chan) = peer_state.outbound_v1_channel_by_id.get_mut(&msg.channel_id) {
                                        if let Ok(msg) = chan.maybe_handle_error_without_close(self.genesis_hash) {
                                                peer_state.pending_msg_events.push(events::MessageSendEvent::SendOpenChannel {
                                                        node_id: *counterparty_node_id,
@@ -6802,6 +7180,10 @@ where
                provided_init_features(&self.default_configuration)
        }
 
+       fn get_genesis_hashes(&self) -> Option<Vec<ChainHash>> {
+               Some(vec![ChainHash::from(&self.genesis_hash[..])])
+       }
+
        fn handle_tx_add_input(&self, counterparty_node_id: &PublicKey, msg: &msgs::TxAddInput) {
                let _: Result<(), _> = handle_error!(self, Err(MsgHandleErrInternal::send_err_msg_no_close(
                        "Dual-funded channels not supported".to_owned(),
@@ -6887,7 +7269,7 @@ pub(crate) fn provided_channel_type_features(config: &UserConfig) -> ChannelType
 
 /// Fetches the set of [`InitFeatures`] flags which are provided by or required by
 /// [`ChannelManager`].
-pub fn provided_init_features(_config: &UserConfig) -> InitFeatures {
+pub fn provided_init_features(config: &UserConfig) -> InitFeatures {
        // Note that if new features are added here which other peers may (eventually) require, we
        // should also add the corresponding (optional) bit to the [`ChannelMessageHandler`] impl for
        // [`ErroringMessageHandler`].
@@ -6903,11 +7285,8 @@ pub fn provided_init_features(_config: &UserConfig) -> InitFeatures {
        features.set_channel_type_optional();
        features.set_scid_privacy_optional();
        features.set_zero_conf_optional();
-       #[cfg(anchors)]
-       { // Attributes are not allowed on if expressions on our current MSRV of 1.41.
-               if _config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx {
-                       features.set_anchors_zero_fee_htlc_tx_optional();
-               }
+       if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx {
+               features.set_anchors_zero_fee_htlc_tx_optional();
        }
        features
 }
@@ -6951,10 +7330,9 @@ impl Writeable for ChannelDetails {
                        (14, user_channel_id_low, required),
                        (16, self.balance_msat, required),
                        (18, self.outbound_capacity_msat, required),
-                       // Note that by the time we get past the required read above, outbound_capacity_msat will be
-                       // filled in, so we can safely unwrap it here.
-                       (19, self.next_outbound_htlc_limit_msat, (default_value, outbound_capacity_msat.0.unwrap() as u64)),
+                       (19, self.next_outbound_htlc_limit_msat, required),
                        (20, self.inbound_capacity_msat, required),
+                       (21, self.next_outbound_htlc_minimum_msat, required),
                        (22, self.confirmations_required, option),
                        (24, self.force_close_spend_delay, option),
                        (26, self.is_outbound, required),
@@ -6991,6 +7369,7 @@ impl Readable for ChannelDetails {
                        // filled in, so we can safely unwrap it here.
                        (19, next_outbound_htlc_limit_msat, (default_value, outbound_capacity_msat.0.unwrap() as u64)),
                        (20, inbound_capacity_msat, required),
+                       (21, next_outbound_htlc_minimum_msat, (default_value, 0)),
                        (22, confirmations_required, option),
                        (24, force_close_spend_delay, option),
                        (26, is_outbound, required),
@@ -7024,6 +7403,7 @@ impl Readable for ChannelDetails {
                        balance_msat: balance_msat.0.unwrap(),
                        outbound_capacity_msat: outbound_capacity_msat.0.unwrap(),
                        next_outbound_htlc_limit_msat: next_outbound_htlc_limit_msat.0.unwrap(),
+                       next_outbound_htlc_minimum_msat: next_outbound_htlc_minimum_msat.0.unwrap(),
                        inbound_capacity_msat: inbound_capacity_msat.0.unwrap(),
                        confirmations_required,
                        confirmations,
@@ -7060,6 +7440,7 @@ impl_writeable_tlv_based_enum!(PendingHTLCRouting,
                (0, payment_preimage, required),
                (2, incoming_cltv_expiry, required),
                (3, payment_metadata, option),
+               (4, payment_data, option), // Added in 0.0.116
        },
 ;);
 
@@ -7070,6 +7451,7 @@ impl_writeable_tlv_based!(PendingHTLCInfo, {
        (6, outgoing_amt_msat, required),
        (8, outgoing_cltv_value, required),
        (9, incoming_amt_msat, option),
+       (10, skimmed_fee_msat, option),
 });
 
 
@@ -7168,6 +7550,7 @@ impl Writeable for ClaimableHTLC {
                        (5, self.total_value_received, option),
                        (6, self.cltv_expiry, required),
                        (8, keysend_preimage, option),
+                       (10, self.counterparty_skimmed_fee_msat, option),
                });
                Ok(())
        }
@@ -7175,24 +7558,19 @@ impl Writeable for ClaimableHTLC {
 
 impl Readable for ClaimableHTLC {
        fn read<R: Read>(reader: &mut R) -> Result<Self, DecodeError> {
-               let mut prev_hop = crate::util::ser::RequiredWrapper(None);
-               let mut value = 0;
-               let mut sender_intended_value = None;
-               let mut payment_data: Option<msgs::FinalOnionHopData> = None;
-               let mut cltv_expiry = 0;
-               let mut total_value_received = None;
-               let mut total_msat = None;
-               let mut keysend_preimage: Option<PaymentPreimage> = None;
-               read_tlv_fields!(reader, {
+               _init_and_read_tlv_fields!(reader, {
                        (0, prev_hop, required),
                        (1, total_msat, option),
-                       (2, value, required),
+                       (2, value_ser, required),
                        (3, sender_intended_value, option),
-                       (4, payment_data, option),
+                       (4, payment_data_opt, option),
                        (5, total_value_received, option),
                        (6, cltv_expiry, required),
-                       (8, keysend_preimage, option)
+                       (8, keysend_preimage, option),
+                       (10, counterparty_skimmed_fee_msat, option),
                });
+               let payment_data: Option<msgs::FinalOnionHopData> = payment_data_opt;
+               let value = value_ser.0.unwrap();
                let onion_payload = match keysend_preimage {
                        Some(p) => {
                                if payment_data.is_some() {
@@ -7221,7 +7599,8 @@ impl Readable for ClaimableHTLC {
                        total_value_received,
                        total_msat: total_msat.unwrap(),
                        onion_payload,
-                       cltv_expiry,
+                       cltv_expiry: cltv_expiry.0.unwrap(),
+                       counterparty_skimmed_fee_msat,
                })
        }
 }
@@ -7359,7 +7738,7 @@ where
                                }
                                number_of_channels += peer_state.channel_by_id.len();
                                for (_, channel) in peer_state.channel_by_id.iter() {
-                                       if !channel.is_funding_initiated() {
+                                       if !channel.context.is_funding_initiated() {
                                                unfunded_channels += 1;
                                        }
                                }
@@ -7371,7 +7750,7 @@ where
                                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                                let peer_state = &mut *peer_state_lock;
                                for (_, channel) in peer_state.channel_by_id.iter() {
-                                       if channel.is_funding_initiated() {
+                                       if channel.context.is_funding_initiated() {
                                                channel.write(writer)?;
                                        }
                                }
@@ -7516,6 +7895,16 @@ where
                        pending_claiming_payments = None;
                }
 
+               let mut in_flight_monitor_updates: Option<HashMap<(&PublicKey, &OutPoint), &Vec<ChannelMonitorUpdate>>> = None;
+               for ((counterparty_id, _), peer_state) in per_peer_state.iter().zip(peer_states.iter()) {
+                       for (funding_outpoint, updates) in peer_state.in_flight_monitor_updates.iter() {
+                               if !updates.is_empty() {
+                                       if in_flight_monitor_updates.is_none() { in_flight_monitor_updates = Some(HashMap::new()); }
+                                       in_flight_monitor_updates.as_mut().unwrap().insert((counterparty_id, funding_outpoint), updates);
+                               }
+                       }
+               }
+
                write_tlv_fields!(writer, {
                        (1, pending_outbound_payments_no_retry, required),
                        (2, pending_intercepted_htlcs, option),
@@ -7526,6 +7915,7 @@ where
                        (7, self.fake_scid_rand_bytes, required),
                        (8, if events_not_backwards_compatible { Some(&*events) } else { None }, option),
                        (9, htlc_purposes, vec_type),
+                       (10, in_flight_monitor_updates, option),
                        (11, self.probing_cookie_secret, required),
                        (13, htlc_onion_fields, optional_vec),
                });
@@ -7657,7 +8047,7 @@ where
        pub default_config: UserConfig,
 
        /// A map from channel funding outpoints to ChannelMonitors for those channels (ie
-       /// value.get_funding_txo() should be the key).
+       /// value.context.get_funding_txo() should be the key).
        ///
        /// If a monitor is inconsistent with the channel state during deserialization the channel will
        /// be force-closed using the data in the ChannelMonitor and the channel will be dropped. This
@@ -7742,41 +8132,33 @@ where
                let mut id_to_peer = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
                let mut short_to_chan_info = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
                let mut channel_closures = VecDeque::new();
-               let mut pending_background_events = Vec::new();
+               let mut close_background_events = Vec::new();
                for _ in 0..channel_count {
                        let mut channel: Channel<<SP::Target as SignerProvider>::Signer> = Channel::read(reader, (
                                &args.entropy_source, &args.signer_provider, best_block_height, &provided_channel_type_features(&args.default_config)
                        ))?;
-                       let funding_txo = channel.get_funding_txo().ok_or(DecodeError::InvalidValue)?;
+                       let funding_txo = channel.context.get_funding_txo().ok_or(DecodeError::InvalidValue)?;
                        funding_txo_set.insert(funding_txo.clone());
                        if let Some(ref mut monitor) = args.channel_monitors.get_mut(&funding_txo) {
-                               if channel.get_latest_complete_monitor_update_id() > monitor.get_latest_update_id() {
-                                       // If the channel is ahead of the monitor, return InvalidValue:
-                                       log_error!(args.logger, "A ChannelMonitor is stale compared to the current ChannelManager! This indicates a potentially-critical violation of the chain::Watch API!");
-                                       log_error!(args.logger, " The ChannelMonitor for channel {} is at update_id {} but the ChannelManager is at update_id {}.",
-                                               log_bytes!(channel.channel_id()), monitor.get_latest_update_id(), channel.get_latest_complete_monitor_update_id());
-                                       log_error!(args.logger, " The chain::Watch API *requires* that monitors are persisted durably before returning,");
-                                       log_error!(args.logger, " client applications must ensure that ChannelMonitor data is always available and the latest to avoid funds loss!");
-                                       log_error!(args.logger, " Without the latest ChannelMonitor we cannot continue without risking funds.");
-                                       log_error!(args.logger, " Please ensure the chain::Watch API requirements are met and file a bug report at https://github.com/lightningdevkit/rust-lightning");
-                                       return Err(DecodeError::InvalidValue);
-                               } else if channel.get_cur_holder_commitment_transaction_number() > monitor.get_cur_holder_commitment_number() ||
+                               if channel.get_cur_holder_commitment_transaction_number() > monitor.get_cur_holder_commitment_number() ||
                                                channel.get_revoked_counterparty_commitment_transaction_number() > monitor.get_min_seen_secret() ||
                                                channel.get_cur_counterparty_commitment_transaction_number() > monitor.get_cur_counterparty_commitment_number() ||
-                                               channel.get_latest_monitor_update_id() < monitor.get_latest_update_id() {
+                                               channel.context.get_latest_monitor_update_id() < monitor.get_latest_update_id() {
                                        // But if the channel is behind of the monitor, close the channel:
                                        log_error!(args.logger, "A ChannelManager is stale compared to the current ChannelMonitor!");
                                        log_error!(args.logger, " The channel will be force-closed and the latest commitment transaction from the ChannelMonitor broadcast.");
                                        log_error!(args.logger, " The ChannelMonitor for channel {} is at update_id {} but the ChannelManager is at update_id {}.",
-                                               log_bytes!(channel.channel_id()), monitor.get_latest_update_id(), channel.get_latest_monitor_update_id());
-                                       let (monitor_update, mut new_failed_htlcs) = channel.force_shutdown(true);
-                                       if let Some(monitor_update) = monitor_update {
-                                               pending_background_events.push(BackgroundEvent::MonitorUpdateRegeneratedOnStartup(monitor_update));
+                                               log_bytes!(channel.context.channel_id()), monitor.get_latest_update_id(), channel.context.get_latest_monitor_update_id());
+                                       let (monitor_update, mut new_failed_htlcs) = channel.context.force_shutdown(true);
+                                       if let Some((counterparty_node_id, funding_txo, update)) = monitor_update {
+                                               close_background_events.push(BackgroundEvent::MonitorUpdateRegeneratedOnStartup {
+                                                       counterparty_node_id, funding_txo, update
+                                               });
                                        }
                                        failed_htlcs.append(&mut new_failed_htlcs);
                                        channel_closures.push_back((events::Event::ChannelClosed {
-                                               channel_id: channel.channel_id(),
-                                               user_channel_id: channel.get_user_id(),
+                                               channel_id: channel.context.channel_id(),
+                                               user_channel_id: channel.context.get_user_id(),
                                                reason: ClosureReason::OutdatedChannelManager
                                        }, None));
                                        for (channel_htlc_source, payment_hash) in channel.inflight_htlc_sources() {
@@ -7794,26 +8176,28 @@ where
                                                        // backwards leg of the HTLC will simply be rejected.
                                                        log_info!(args.logger,
                                                                "Failing HTLC with hash {} as it is missing in the ChannelMonitor for channel {} but was present in the (stale) ChannelManager",
-                                                               log_bytes!(channel.channel_id()), log_bytes!(payment_hash.0));
-                                                       failed_htlcs.push((channel_htlc_source.clone(), *payment_hash, channel.get_counterparty_node_id(), channel.channel_id()));
+                                                               log_bytes!(channel.context.channel_id()), log_bytes!(payment_hash.0));
+                                                       failed_htlcs.push((channel_htlc_source.clone(), *payment_hash, channel.context.get_counterparty_node_id(), channel.context.channel_id()));
                                                }
                                        }
                                } else {
-                                       log_info!(args.logger, "Successfully loaded channel {}", log_bytes!(channel.channel_id()));
-                                       if let Some(short_channel_id) = channel.get_short_channel_id() {
-                                               short_to_chan_info.insert(short_channel_id, (channel.get_counterparty_node_id(), channel.channel_id()));
+                                       log_info!(args.logger, "Successfully loaded channel {} at update_id {} against monitor at update id {}",
+                                               log_bytes!(channel.context.channel_id()), channel.context.get_latest_monitor_update_id(),
+                                               monitor.get_latest_update_id());
+                                       if let Some(short_channel_id) = channel.context.get_short_channel_id() {
+                                               short_to_chan_info.insert(short_channel_id, (channel.context.get_counterparty_node_id(), channel.context.channel_id()));
                                        }
-                                       if channel.is_funding_initiated() {
-                                               id_to_peer.insert(channel.channel_id(), channel.get_counterparty_node_id());
+                                       if channel.context.is_funding_initiated() {
+                                               id_to_peer.insert(channel.context.channel_id(), channel.context.get_counterparty_node_id());
                                        }
-                                       match peer_channels.entry(channel.get_counterparty_node_id()) {
+                                       match peer_channels.entry(channel.context.get_counterparty_node_id()) {
                                                hash_map::Entry::Occupied(mut entry) => {
                                                        let by_id_map = entry.get_mut();
-                                                       by_id_map.insert(channel.channel_id(), channel);
+                                                       by_id_map.insert(channel.context.channel_id(), channel);
                                                },
                                                hash_map::Entry::Vacant(entry) => {
                                                        let mut by_id_map = HashMap::new();
-                                                       by_id_map.insert(channel.channel_id(), channel);
+                                                       by_id_map.insert(channel.context.channel_id(), channel);
                                                        entry.insert(by_id_map);
                                                }
                                        }
@@ -7822,14 +8206,14 @@ where
                                // If we were persisted and shut down while the initial ChannelMonitor persistence
                                // was in-progress, we never broadcasted the funding transaction and can still
                                // safely discard the channel.
-                               let _ = channel.force_shutdown(false);
+                               let _ = channel.context.force_shutdown(false);
                                channel_closures.push_back((events::Event::ChannelClosed {
-                                       channel_id: channel.channel_id(),
-                                       user_channel_id: channel.get_user_id(),
+                                       channel_id: channel.context.channel_id(),
+                                       user_channel_id: channel.context.get_user_id(),
                                        reason: ClosureReason::DisconnectedPeer,
                                }, None));
                        } else {
-                               log_error!(args.logger, "Missing ChannelMonitor for channel {} needed by ChannelManager.", log_bytes!(channel.channel_id()));
+                               log_error!(args.logger, "Missing ChannelMonitor for channel {} needed by ChannelManager.", log_bytes!(channel.context.channel_id()));
                                log_error!(args.logger, " The chain::Watch API *requires* that monitors are persisted durably before returning,");
                                log_error!(args.logger, " client applications must ensure that ChannelMonitor data is always available and the latest to avoid funds loss!");
                                log_error!(args.logger, " Without the ChannelMonitor we cannot continue without risking funds.");
@@ -7846,7 +8230,7 @@ where
                                        update_id: CLOSED_CHANNEL_UPDATE_ID,
                                        updates: vec![ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast: true }],
                                };
-                               pending_background_events.push(BackgroundEvent::MonitorUpdateRegeneratedOnStartup((*funding_txo, monitor_update)));
+                               close_background_events.push(BackgroundEvent::ClosingMonitorUpdateRegeneratedOnStartup((*funding_txo, monitor_update)));
                        }
                }
 
@@ -7875,17 +8259,27 @@ where
                        claimable_htlcs_list.push((payment_hash, previous_hops));
                }
 
+               let peer_state_from_chans = |channel_by_id| {
+                       PeerState {
+                               channel_by_id,
+                               outbound_v1_channel_by_id: HashMap::new(),
+                               inbound_v1_channel_by_id: HashMap::new(),
+                               latest_features: InitFeatures::empty(),
+                               pending_msg_events: Vec::new(),
+                               in_flight_monitor_updates: BTreeMap::new(),
+                               monitor_update_blocked_actions: BTreeMap::new(),
+                               actions_blocking_raa_monitor_updates: BTreeMap::new(),
+                               is_connected: false,
+                       }
+               };
+
                let peer_count: u64 = Readable::read(reader)?;
                let mut per_peer_state = HashMap::with_capacity(cmp::min(peer_count as usize, MAX_ALLOC_SIZE/mem::size_of::<(PublicKey, Mutex<PeerState<<SP::Target as SignerProvider>::Signer>>)>()));
                for _ in 0..peer_count {
                        let peer_pubkey = Readable::read(reader)?;
-                       let peer_state = PeerState {
-                               channel_by_id: peer_channels.remove(&peer_pubkey).unwrap_or(HashMap::new()),
-                               latest_features: Readable::read(reader)?,
-                               pending_msg_events: Vec::new(),
-                               monitor_update_blocked_actions: BTreeMap::new(),
-                               is_connected: false,
-                       };
+                       let peer_chans = peer_channels.remove(&peer_pubkey).unwrap_or(HashMap::new());
+                       let mut peer_state = peer_state_from_chans(peer_chans);
+                       peer_state.latest_features = Readable::read(reader)?;
                        per_peer_state.insert(peer_pubkey, Mutex::new(peer_state));
                }
 
@@ -7947,8 +8341,9 @@ where
                let mut claimable_htlc_purposes = None;
                let mut claimable_htlc_onion_fields = None;
                let mut pending_claiming_payments = Some(HashMap::new());
-               let mut monitor_update_blocked_actions_per_peer = Some(Vec::new());
+               let mut monitor_update_blocked_actions_per_peer: Option<Vec<(_, BTreeMap<_, Vec<_>>)>> = Some(Vec::new());
                let mut events_override = None;
+               let mut in_flight_monitor_updates: Option<HashMap<(PublicKey, OutPoint), Vec<ChannelMonitorUpdate>>> = None;
                read_tlv_fields!(reader, {
                        (1, pending_outbound_payments_no_retry, option),
                        (2, pending_intercepted_htlcs, option),
@@ -7959,6 +8354,7 @@ where
                        (7, fake_scid_rand_bytes, option),
                        (8, events_override, option),
                        (9, claimable_htlc_purposes, vec_type),
+                       (10, in_flight_monitor_updates, option),
                        (11, probing_cookie_secret, option),
                        (13, claimable_htlc_onion_fields, optional_vec),
                });
@@ -7992,6 +8388,103 @@ where
                        retry_lock: Mutex::new(())
                };
 
+               // We have to replay (or skip, if they were completed after we wrote the `ChannelManager`)
+               // each `ChannelMonitorUpdate` in `in_flight_monitor_updates`. After doing so, we have to
+               // check that each channel we have isn't newer than the latest `ChannelMonitorUpdate`(s) we
+               // replayed, and for each monitor update we have to replay we have to ensure there's a
+               // `ChannelMonitor` for it.
+               //
+               // In order to do so we first walk all of our live channels (so that we can check their
+               // state immediately after doing the update replays, when we have the `update_id`s
+               // available) and then walk any remaining in-flight updates.
+               //
+               // Because the actual handling of the in-flight updates is the same, it's macro'ized here:
+               let mut pending_background_events = Vec::new();
+               macro_rules! handle_in_flight_updates {
+                       ($counterparty_node_id: expr, $chan_in_flight_upds: expr, $funding_txo: expr,
+                        $monitor: expr, $peer_state: expr, $channel_info_log: expr
+                       ) => { {
+                               let mut max_in_flight_update_id = 0;
+                               $chan_in_flight_upds.retain(|upd| upd.update_id > $monitor.get_latest_update_id());
+                               for update in $chan_in_flight_upds.iter() {
+                                       log_trace!(args.logger, "Replaying ChannelMonitorUpdate {} for {}channel {}",
+                                               update.update_id, $channel_info_log, log_bytes!($funding_txo.to_channel_id()));
+                                       max_in_flight_update_id = cmp::max(max_in_flight_update_id, update.update_id);
+                                       pending_background_events.push(
+                                               BackgroundEvent::MonitorUpdateRegeneratedOnStartup {
+                                                       counterparty_node_id: $counterparty_node_id,
+                                                       funding_txo: $funding_txo,
+                                                       update: update.clone(),
+                                               });
+                               }
+                               if $peer_state.in_flight_monitor_updates.insert($funding_txo, $chan_in_flight_upds).is_some() {
+                                       log_error!(args.logger, "Duplicate in-flight monitor update set for the same channel!");
+                                       return Err(DecodeError::InvalidValue);
+                               }
+                               max_in_flight_update_id
+                       } }
+               }
+
+               for (counterparty_id, peer_state_mtx) in per_peer_state.iter_mut() {
+                       let mut peer_state_lock = peer_state_mtx.lock().unwrap();
+                       let peer_state = &mut *peer_state_lock;
+                       for (_, chan) in peer_state.channel_by_id.iter() {
+                               // Channels that were persisted have to be funded, otherwise they should have been
+                               // discarded.
+                               let funding_txo = chan.context.get_funding_txo().ok_or(DecodeError::InvalidValue)?;
+                               let monitor = args.channel_monitors.get(&funding_txo)
+                                       .expect("We already checked for monitor presence when loading channels");
+                               let mut max_in_flight_update_id = monitor.get_latest_update_id();
+                               if let Some(in_flight_upds) = &mut in_flight_monitor_updates {
+                                       if let Some(mut chan_in_flight_upds) = in_flight_upds.remove(&(*counterparty_id, funding_txo)) {
+                                               max_in_flight_update_id = cmp::max(max_in_flight_update_id,
+                                                       handle_in_flight_updates!(*counterparty_id, chan_in_flight_upds,
+                                                               funding_txo, monitor, peer_state, ""));
+                                       }
+                               }
+                               if chan.get_latest_unblocked_monitor_update_id() > max_in_flight_update_id {
+                                       // If the channel is ahead of the monitor, return InvalidValue:
+                                       log_error!(args.logger, "A ChannelMonitor is stale compared to the current ChannelManager! This indicates a potentially-critical violation of the chain::Watch API!");
+                                       log_error!(args.logger, " The ChannelMonitor for channel {} is at update_id {} with update_id through {} in-flight",
+                                               log_bytes!(chan.context.channel_id()), monitor.get_latest_update_id(), max_in_flight_update_id);
+                                       log_error!(args.logger, " but the ChannelManager is at update_id {}.", chan.get_latest_unblocked_monitor_update_id());
+                                       log_error!(args.logger, " The chain::Watch API *requires* that monitors are persisted durably before returning,");
+                                       log_error!(args.logger, " client applications must ensure that ChannelMonitor data is always available and the latest to avoid funds loss!");
+                                       log_error!(args.logger, " Without the latest ChannelMonitor we cannot continue without risking funds.");
+                                       log_error!(args.logger, " Please ensure the chain::Watch API requirements are met and file a bug report at https://github.com/lightningdevkit/rust-lightning");
+                                       return Err(DecodeError::InvalidValue);
+                               }
+                       }
+               }
+
+               if let Some(in_flight_upds) = in_flight_monitor_updates {
+                       for ((counterparty_id, funding_txo), mut chan_in_flight_updates) in in_flight_upds {
+                               if let Some(monitor) = args.channel_monitors.get(&funding_txo) {
+                                       // Now that we've removed all the in-flight monitor updates for channels that are
+                                       // still open, we need to replay any monitor updates that are for closed channels,
+                                       // creating the neccessary peer_state entries as we go.
+                                       let peer_state_mutex = per_peer_state.entry(counterparty_id).or_insert_with(|| {
+                                               Mutex::new(peer_state_from_chans(HashMap::new()))
+                                       });
+                                       let mut peer_state = peer_state_mutex.lock().unwrap();
+                                       handle_in_flight_updates!(counterparty_id, chan_in_flight_updates,
+                                               funding_txo, monitor, peer_state, "closed ");
+                               } else {
+                                       log_error!(args.logger, "A ChannelMonitor is missing even though we have in-flight updates for it! This indicates a potentially-critical violation of the chain::Watch API!");
+                                       log_error!(args.logger, " The ChannelMonitor for channel {} is missing.",
+                                               log_bytes!(funding_txo.to_channel_id()));
+                                       log_error!(args.logger, " The chain::Watch API *requires* that monitors are persisted durably before returning,");
+                                       log_error!(args.logger, " client applications must ensure that ChannelMonitor data is always available and the latest to avoid funds loss!");
+                                       log_error!(args.logger, " Without the latest ChannelMonitor we cannot continue without risking funds.");
+                                       log_error!(args.logger, " Please ensure the chain::Watch API requirements are met and file a bug report at https://github.com/lightningdevkit/rust-lightning");
+                                       return Err(DecodeError::InvalidValue);
+                               }
+                       }
+               }
+
+               // Note that we have to do the above replays before we push new monitor updates.
+               pending_background_events.append(&mut close_background_events);
+
                {
                        // If we're tracking pending payments, ensure we haven't lost any by looking at the
                        // ChannelMonitor data for any channels for which we do not have authorative state
@@ -8191,25 +8684,25 @@ where
                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                        let peer_state = &mut *peer_state_lock;
                        for (chan_id, chan) in peer_state.channel_by_id.iter_mut() {
-                               if chan.outbound_scid_alias() == 0 {
+                               if chan.context.outbound_scid_alias() == 0 {
                                        let mut outbound_scid_alias;
                                        loop {
                                                outbound_scid_alias = fake_scid::Namespace::OutboundAlias
                                                        .get_fake_scid(best_block_height, &genesis_hash, fake_scid_rand_bytes.as_ref().unwrap(), &args.entropy_source);
                                                if outbound_scid_aliases.insert(outbound_scid_alias) { break; }
                                        }
-                                       chan.set_outbound_scid_alias(outbound_scid_alias);
-                               } else if !outbound_scid_aliases.insert(chan.outbound_scid_alias()) {
+                                       chan.context.set_outbound_scid_alias(outbound_scid_alias);
+                               } else if !outbound_scid_aliases.insert(chan.context.outbound_scid_alias()) {
                                        // Note that in rare cases its possible to hit this while reading an older
                                        // channel if we just happened to pick a colliding outbound alias above.
-                                       log_error!(args.logger, "Got duplicate outbound SCID alias; {}", chan.outbound_scid_alias());
+                                       log_error!(args.logger, "Got duplicate outbound SCID alias; {}", chan.context.outbound_scid_alias());
                                        return Err(DecodeError::InvalidValue);
                                }
-                               if chan.is_usable() {
-                                       if short_to_chan_info.insert(chan.outbound_scid_alias(), (chan.get_counterparty_node_id(), *chan_id)).is_some() {
+                               if chan.context.is_usable() {
+                                       if short_to_chan_info.insert(chan.context.outbound_scid_alias(), (chan.context.get_counterparty_node_id(), *chan_id)).is_some() {
                                                // Note that in rare cases its possible to hit this while reading an older
                                                // channel if we just happened to pick a colliding outbound alias above.
-                                               log_error!(args.logger, "Got duplicate outbound SCID alias; {}", chan.outbound_scid_alias());
+                                               log_error!(args.logger, "Got duplicate outbound SCID alias; {}", chan.context.outbound_scid_alias());
                                                return Err(DecodeError::InvalidValue);
                                        }
                                }
@@ -8272,7 +8765,21 @@ where
                }
 
                for (node_id, monitor_update_blocked_actions) in monitor_update_blocked_actions_per_peer.unwrap() {
-                       if let Some(peer_state) = per_peer_state.get_mut(&node_id) {
+                       if let Some(peer_state) = per_peer_state.get(&node_id) {
+                               for (_, actions) in monitor_update_blocked_actions.iter() {
+                                       for action in actions.iter() {
+                                               if let MonitorUpdateCompletionAction::EmitEventAndFreeOtherChannel {
+                                                       downstream_counterparty_and_funding_outpoint:
+                                                               Some((blocked_node_id, blocked_channel_outpoint, blocking_action)), ..
+                                               } = action {
+                                                       if let Some(blocked_peer_state) = per_peer_state.get(&blocked_node_id) {
+                                                               blocked_peer_state.lock().unwrap().actions_blocking_raa_monitor_updates
+                                                                       .entry(blocked_channel_outpoint.to_channel_id())
+                                                                       .or_insert_with(Vec::new).push(blocking_action.clone());
+                                                       }
+                                               }
+                                       }
+                               }
                                peer_state.lock().unwrap().monitor_update_blocked_actions = monitor_update_blocked_actions;
                        } else {
                                log_error!(args.logger, "Got blocked actions without a per-peer-state for {}", node_id);
@@ -8314,6 +8821,8 @@ where
                        pending_events_processor: AtomicBool::new(false),
                        pending_background_events: Mutex::new(pending_background_events),
                        total_consistency_lock: RwLock::new(()),
+                       #[cfg(debug_assertions)]
+                       background_events_processed_since_startup: AtomicBool::new(false),
                        persistence_notifier: Notifier::new(),
 
                        entropy_source: args.entropy_source,
@@ -8348,12 +8857,12 @@ mod tests {
        use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
        use crate::ln::channelmanager::{inbound_payment, PaymentId, PaymentSendFailure, RecipientOnionFields, InterceptId};
        use crate::ln::functional_test_utils::*;
-       use crate::ln::msgs;
+       use crate::ln::msgs::{self, ErrorAction};
        use crate::ln::msgs::ChannelMessageHandler;
        use crate::routing::router::{PaymentParameters, RouteParameters, find_route};
        use crate::util::errors::APIError;
        use crate::util::test_utils;
-       use crate::util::config::ChannelConfig;
+       use crate::util::config::{ChannelConfig, ChannelConfigUpdate};
        use crate::sign::EntropySource;
 
        #[test]
@@ -8562,13 +9071,26 @@ mod tests {
 
        #[test]
        fn test_keysend_dup_payment_hash() {
+               do_test_keysend_dup_payment_hash(false);
+               do_test_keysend_dup_payment_hash(true);
+       }
+
+       fn do_test_keysend_dup_payment_hash(accept_mpp_keysend: bool) {
                // (1): Test that a keysend payment with a duplicate payment hash to an existing pending
                //      outbound regular payment fails as expected.
                // (2): Test that a regular payment with a duplicate payment hash to an existing keysend payment
                //      fails as expected.
+               // (3): Test that a keysend payment with a duplicate payment hash to an existing keysend
+               //      payment fails as expected. When `accept_mpp_keysend` is false, this tests that we
+               //      reject MPP keysend payments, since in this case where the payment has no payment
+               //      secret, a keysend payment with a duplicate hash is basically an MPP keysend. If
+               //      `accept_mpp_keysend` is true, this tests that we only accept MPP keysends with
+               //      payment secrets and reject otherwise.
                let chanmon_cfgs = create_chanmon_cfgs(2);
                let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
-               let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+               let mut mpp_keysend_cfg = test_default_channel_config();
+               mpp_keysend_cfg.accept_mpp_keysend = accept_mpp_keysend;
+               let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, Some(mpp_keysend_cfg)]);
                let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
                create_announced_chan_between_nodes(&nodes, 0, 1);
                let scorer = test_utils::TestScorer::new();
@@ -8580,7 +9102,7 @@ mod tests {
 
                // Next, attempt a keysend payment and make sure it fails.
                let route_params = RouteParameters {
-                       payment_params: PaymentParameters::for_keysend(expected_route.last().unwrap().node.get_our_node_id(), TEST_FINAL_CLTV),
+                       payment_params: PaymentParameters::for_keysend(expected_route.last().unwrap().node.get_our_node_id(), TEST_FINAL_CLTV, false),
                        final_value_msat: 100_000,
                };
                let route = find_route(
@@ -8657,6 +9179,53 @@ mod tests {
 
                // Finally, succeed the keysend payment.
                claim_payment(&nodes[0], &expected_route, payment_preimage);
+
+               // To start (3), send a keysend payment but don't claim it.
+               let payment_id_1 = PaymentId([44; 32]);
+               let payment_hash = nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage),
+                       RecipientOnionFields::spontaneous_empty(), payment_id_1).unwrap();
+               check_added_monitors!(nodes[0], 1);
+               let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 1);
+               let event = events.pop().unwrap();
+               let path = vec![&nodes[1]];
+               pass_along_path(&nodes[0], &path, 100_000, payment_hash, None, event, true, Some(payment_preimage));
+
+               // Next, attempt a keysend payment and make sure it fails.
+               let route_params = RouteParameters {
+                       payment_params: PaymentParameters::for_keysend(expected_route.last().unwrap().node.get_our_node_id(), TEST_FINAL_CLTV, false),
+                       final_value_msat: 100_000,
+               };
+               let route = find_route(
+                       &nodes[0].node.get_our_node_id(), &route_params, &nodes[0].network_graph,
+                       None, nodes[0].logger, &scorer, &(), &random_seed_bytes
+               ).unwrap();
+               let payment_id_2 = PaymentId([45; 32]);
+               nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage),
+                       RecipientOnionFields::spontaneous_empty(), payment_id_2).unwrap();
+               check_added_monitors!(nodes[0], 1);
+               let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 1);
+               let ev = events.drain(..).next().unwrap();
+               let payment_event = SendEvent::from_event(ev);
+               nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
+               check_added_monitors!(nodes[1], 0);
+               commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false);
+               expect_pending_htlcs_forwardable!(nodes[1]);
+               expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
+               check_added_monitors!(nodes[1], 1);
+               let updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
+               assert!(updates.update_add_htlcs.is_empty());
+               assert!(updates.update_fulfill_htlcs.is_empty());
+               assert_eq!(updates.update_fail_htlcs.len(), 1);
+               assert!(updates.update_fail_malformed_htlcs.is_empty());
+               assert!(updates.update_fee.is_none());
+               nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
+               commitment_signed_dance!(nodes[0], nodes[1], updates.commitment_signed, true, true);
+               expect_payment_failed!(nodes[0], payment_hash, true);
+
+               // Finally, claim the original payment.
+               claim_payment(&nodes[0], &expected_route, payment_preimage);
        }
 
        #[test]
@@ -8673,7 +9242,7 @@ mod tests {
 
                let _chan = create_chan_between_nodes(&nodes[0], &nodes[1]);
                let route_params = RouteParameters {
-                       payment_params: PaymentParameters::for_keysend(payee_pubkey, 40),
+                       payment_params: PaymentParameters::for_keysend(payee_pubkey, 40, false),
                        final_value_msat: 10_000,
                };
                let network_graph = nodes[0].network_graph.clone();
@@ -8706,10 +9275,13 @@ mod tests {
 
        #[test]
        fn test_keysend_msg_with_secret_err() {
-               // Test that we error as expected if we receive a keysend payment that includes a payment secret.
+               // Test that we error as expected if we receive a keysend payment that includes a payment
+               // secret when we don't support MPP keysend.
+               let mut reject_mpp_keysend_cfg = test_default_channel_config();
+               reject_mpp_keysend_cfg.accept_mpp_keysend = false;
                let chanmon_cfgs = create_chanmon_cfgs(2);
                let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
-               let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+               let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, Some(reject_mpp_keysend_cfg)]);
                let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 
                let payer_pubkey = nodes[0].node.get_our_node_id();
@@ -8717,7 +9289,7 @@ mod tests {
 
                let _chan = create_chan_between_nodes(&nodes[0], &nodes[1]);
                let route_params = RouteParameters {
-                       payment_params: PaymentParameters::for_keysend(payee_pubkey, 40),
+                       payment_params: PaymentParameters::for_keysend(payee_pubkey, 40, false),
                        final_value_msat: 10_000,
                };
                let network_graph = nodes[0].network_graph.clone();
@@ -9072,12 +9644,14 @@ mod tests {
                                &SecretKey::from_slice(&nodes[1].keys_manager.get_secure_random_bytes()).unwrap());
                        peer_pks.push(random_pk);
                        nodes[1].node.peer_connected(&random_pk, &msgs::Init {
-                               features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap();
+                               features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+                       }, true).unwrap();
                }
                let last_random_pk = PublicKey::from_secret_key(&nodes[0].node.secp_ctx,
                        &SecretKey::from_slice(&nodes[1].keys_manager.get_secure_random_bytes()).unwrap());
                nodes[1].node.peer_connected(&last_random_pk, &msgs::Init {
-                       features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap_err();
+                       features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+               }, true).unwrap_err();
 
                // Also importantly, because nodes[0] isn't "protected", we will refuse a reconnection from
                // them if we have too many un-channel'd peers.
@@ -9088,13 +9662,16 @@ mod tests {
                        if let Event::ChannelClosed { .. } = ev { } else { panic!(); }
                }
                nodes[1].node.peer_connected(&last_random_pk, &msgs::Init {
-                       features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap();
+                       features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+               }, true).unwrap();
                nodes[1].node.peer_connected(&nodes[0].node.get_our_node_id(), &msgs::Init {
-                       features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap_err();
+                       features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+               }, true).unwrap_err();
 
                // but of course if the connection is outbound its allowed...
                nodes[1].node.peer_connected(&nodes[0].node.get_our_node_id(), &msgs::Init {
-                       features: nodes[0].node.init_features(), remote_network_address: None }, false).unwrap();
+                       features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+               }, false).unwrap();
                nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());
 
                // Now nodes[0] is disconnected but still has a pending, un-funded channel lying around.
@@ -9118,7 +9695,8 @@ mod tests {
                // "protected" and can connect again.
                mine_transaction(&nodes[1], funding_tx.as_ref().unwrap());
                nodes[1].node.peer_connected(&nodes[0].node.get_our_node_id(), &msgs::Init {
-                       features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap();
+                       features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+               }, true).unwrap();
                get_event_msg!(nodes[1], MessageSendEvent::SendChannelReestablish, nodes[0].node.get_our_node_id());
 
                // Further, because the first channel was funded, we can open another channel with
@@ -9183,7 +9761,8 @@ mod tests {
                        let random_pk = PublicKey::from_secret_key(&nodes[0].node.secp_ctx,
                                &SecretKey::from_slice(&nodes[1].keys_manager.get_secure_random_bytes()).unwrap());
                        nodes[1].node.peer_connected(&random_pk, &msgs::Init {
-                               features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap();
+                               features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+                       }, true).unwrap();
 
                        nodes[1].node.handle_open_channel(&random_pk, &open_channel_msg);
                        let events = nodes[1].node.get_and_clear_pending_events();
@@ -9201,7 +9780,8 @@ mod tests {
                let last_random_pk = PublicKey::from_secret_key(&nodes[0].node.secp_ctx,
                        &SecretKey::from_slice(&nodes[1].keys_manager.get_secure_random_bytes()).unwrap());
                nodes[1].node.peer_connected(&last_random_pk, &msgs::Init {
-                       features: nodes[0].node.init_features(), remote_network_address: None }, true).unwrap();
+                       features: nodes[0].node.init_features(), networks: None, remote_network_address: None
+               }, true).unwrap();
                nodes[1].node.handle_open_channel(&last_random_pk, &open_channel_msg);
                let events = nodes[1].node.get_and_clear_pending_events();
                match events[0] {
@@ -9229,7 +9809,94 @@ mod tests {
                get_event_msg!(nodes[1], MessageSendEvent::SendAcceptChannel, last_random_pk);
        }
 
-       #[cfg(anchors)]
+       #[test]
+       fn reject_excessively_underpaying_htlcs() {
+               let chanmon_cfg = create_chanmon_cfgs(1);
+               let node_cfg = create_node_cfgs(1, &chanmon_cfg);
+               let node_chanmgr = create_node_chanmgrs(1, &node_cfg, &[None]);
+               let node = create_network(1, &node_cfg, &node_chanmgr);
+               let sender_intended_amt_msat = 100;
+               let extra_fee_msat = 10;
+               let hop_data = msgs::OnionHopData {
+                       amt_to_forward: 100,
+                       outgoing_cltv_value: 42,
+                       format: msgs::OnionHopDataFormat::FinalNode {
+                               keysend_preimage: None,
+                               payment_metadata: None,
+                               payment_data: Some(msgs::FinalOnionHopData {
+                                       payment_secret: PaymentSecret([0; 32]), total_msat: sender_intended_amt_msat,
+                               }),
+                       }
+               };
+               // Check that if the amount we received + the penultimate hop extra fee is less than the sender
+               // intended amount, we fail the payment.
+               if let Err(crate::ln::channelmanager::ReceiveError { err_code, .. }) =
+                       node[0].node.construct_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
+                               sender_intended_amt_msat - extra_fee_msat - 1, 42, None, true, Some(extra_fee_msat))
+               {
+                       assert_eq!(err_code, 19);
+               } else { panic!(); }
+
+               // If amt_received + extra_fee is equal to the sender intended amount, we're fine.
+               let hop_data = msgs::OnionHopData { // This is the same hop_data as above, OnionHopData doesn't implement Clone
+                       amt_to_forward: 100,
+                       outgoing_cltv_value: 42,
+                       format: msgs::OnionHopDataFormat::FinalNode {
+                               keysend_preimage: None,
+                               payment_metadata: None,
+                               payment_data: Some(msgs::FinalOnionHopData {
+                                       payment_secret: PaymentSecret([0; 32]), total_msat: sender_intended_amt_msat,
+                               }),
+                       }
+               };
+               assert!(node[0].node.construct_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
+                       sender_intended_amt_msat - extra_fee_msat, 42, None, true, Some(extra_fee_msat)).is_ok());
+       }
+
+       #[test]
+       fn test_inbound_anchors_manual_acceptance() {
+               // Tests that we properly limit inbound channels when we have the manual-channel-acceptance
+               // flag set and (sometimes) accept channels as 0conf.
+               let mut anchors_cfg = test_default_channel_config();
+               anchors_cfg.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+
+               let mut anchors_manual_accept_cfg = anchors_cfg.clone();
+               anchors_manual_accept_cfg.manually_accept_inbound_channels = true;
+
+               let chanmon_cfgs = create_chanmon_cfgs(3);
+               let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+               let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs,
+                       &[Some(anchors_cfg.clone()), Some(anchors_cfg.clone()), Some(anchors_manual_accept_cfg.clone())]);
+               let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+
+               nodes[0].node.create_channel(nodes[1].node.get_our_node_id(), 100_000, 0, 42, None).unwrap();
+               let open_channel_msg = get_event_msg!(nodes[0], MessageSendEvent::SendOpenChannel, nodes[1].node.get_our_node_id());
+
+               nodes[1].node.handle_open_channel(&nodes[0].node.get_our_node_id(), &open_channel_msg);
+               assert!(nodes[1].node.get_and_clear_pending_events().is_empty());
+               let msg_events = nodes[1].node.get_and_clear_pending_msg_events();
+               match &msg_events[0] {
+                       MessageSendEvent::HandleError { node_id, action } => {
+                               assert_eq!(*node_id, nodes[0].node.get_our_node_id());
+                               match action {
+                                       ErrorAction::SendErrorMessage { msg } =>
+                                               assert_eq!(msg.data, "No channels with anchor outputs accepted".to_owned()),
+                                       _ => panic!("Unexpected error action"),
+                               }
+                       }
+                       _ => panic!("Unexpected event"),
+               }
+
+               nodes[2].node.handle_open_channel(&nodes[0].node.get_our_node_id(), &open_channel_msg);
+               let events = nodes[2].node.get_and_clear_pending_events();
+               match events[0] {
+                       Event::OpenChannelRequest { temporary_channel_id, .. } =>
+                               nodes[2].node.accept_inbound_channel(&temporary_channel_id, &nodes[0].node.get_our_node_id(), 23).unwrap(),
+                       _ => panic!("Unexpected event"),
+               }
+               get_event_msg!(nodes[2], MessageSendEvent::SendAcceptChannel, nodes[0].node.get_our_node_id());
+       }
+
        #[test]
        fn test_anchors_zero_fee_htlc_tx_fallback() {
                // Tests that if both nodes support anchors, but the remote node does not want to accept
@@ -9264,6 +9931,62 @@ mod tests {
 
                check_closed_event!(nodes[1], 1, ClosureReason::HolderForceClosed);
        }
+
+       #[test]
+       fn test_update_channel_config() {
+               let chanmon_cfg = create_chanmon_cfgs(2);
+               let node_cfg = create_node_cfgs(2, &chanmon_cfg);
+               let mut user_config = test_default_channel_config();
+               let node_chanmgr = create_node_chanmgrs(2, &node_cfg, &[Some(user_config), Some(user_config)]);
+               let nodes = create_network(2, &node_cfg, &node_chanmgr);
+               let _ = create_announced_chan_between_nodes(&nodes, 0, 1);
+               let channel = &nodes[0].node.list_channels()[0];
+
+               nodes[0].node.update_channel_config(&channel.counterparty.node_id, &[channel.channel_id], &user_config.channel_config).unwrap();
+               let events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 0);
+
+               user_config.channel_config.forwarding_fee_base_msat += 10;
+               nodes[0].node.update_channel_config(&channel.counterparty.node_id, &[channel.channel_id], &user_config.channel_config).unwrap();
+               assert_eq!(nodes[0].node.list_channels()[0].config.unwrap().forwarding_fee_base_msat, user_config.channel_config.forwarding_fee_base_msat);
+               let events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 1);
+               match &events[0] {
+                       MessageSendEvent::BroadcastChannelUpdate { .. } => {},
+                       _ => panic!("expected BroadcastChannelUpdate event"),
+               }
+
+               nodes[0].node.update_partial_channel_config(&channel.counterparty.node_id, &[channel.channel_id], &ChannelConfigUpdate::default()).unwrap();
+               let events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 0);
+
+               let new_cltv_expiry_delta = user_config.channel_config.cltv_expiry_delta + 6;
+               nodes[0].node.update_partial_channel_config(&channel.counterparty.node_id, &[channel.channel_id], &ChannelConfigUpdate {
+                       cltv_expiry_delta: Some(new_cltv_expiry_delta),
+                       ..Default::default()
+               }).unwrap();
+               assert_eq!(nodes[0].node.list_channels()[0].config.unwrap().cltv_expiry_delta, new_cltv_expiry_delta);
+               let events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 1);
+               match &events[0] {
+                       MessageSendEvent::BroadcastChannelUpdate { .. } => {},
+                       _ => panic!("expected BroadcastChannelUpdate event"),
+               }
+
+               let new_fee = user_config.channel_config.forwarding_fee_proportional_millionths + 100;
+               nodes[0].node.update_partial_channel_config(&channel.counterparty.node_id, &[channel.channel_id], &ChannelConfigUpdate {
+                       forwarding_fee_proportional_millionths: Some(new_fee),
+                       ..Default::default()
+               }).unwrap();
+               assert_eq!(nodes[0].node.list_channels()[0].config.unwrap().cltv_expiry_delta, new_cltv_expiry_delta);
+               assert_eq!(nodes[0].node.list_channels()[0].config.unwrap().forwarding_fee_proportional_millionths, new_fee);
+               let events = nodes[0].node.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), 1);
+               match &events[0] {
+                       MessageSendEvent::BroadcastChannelUpdate { .. } => {},
+                       _ => panic!("expected BroadcastChannelUpdate event"),
+               }
+       }
 }
 
 #[cfg(ldk_bench)]
@@ -9345,8 +10068,12 @@ pub mod bench {
                });
                let node_b_holder = ANodeHolder { node: &node_b };
 
-               node_a.peer_connected(&node_b.get_our_node_id(), &Init { features: node_b.init_features(), remote_network_address: None }, true).unwrap();
-               node_b.peer_connected(&node_a.get_our_node_id(), &Init { features: node_a.init_features(), remote_network_address: None }, false).unwrap();
+               node_a.peer_connected(&node_b.get_our_node_id(), &Init {
+                       features: node_b.init_features(), networks: None, remote_network_address: None
+               }, true).unwrap();
+               node_b.peer_connected(&node_a.get_our_node_id(), &Init {
+                       features: node_a.init_features(), networks: None, remote_network_address: None
+               }, false).unwrap();
                node_a.create_channel(node_b.get_our_node_id(), 8_000_000, 100_000_000, 42, None).unwrap();
                node_b.handle_open_channel(&node_a.get_our_node_id(), &get_event_msg!(node_a_holder, MessageSendEvent::SendOpenChannel, node_b.get_our_node_id()));
                node_a.handle_accept_channel(&node_b.get_our_node_id(), &get_event_msg!(node_b_holder, MessageSendEvent::SendAcceptChannel, node_a.get_our_node_id()));