Add splicing feature flag (also triggers dual_funding)
[rust-lightning] / lightning / src / ln / channel.rs
index efafe56d548e334bac486dfb783e169289a81944..c02659cd0b01cc83548b988c362929074c56808d 100644 (file)
@@ -50,7 +50,6 @@ use crate::util::scid_utils::scid_from_parts;
 use crate::io;
 use crate::prelude::*;
 use core::{cmp,mem,fmt};
-use core::convert::TryInto;
 use core::ops::Deref;
 #[cfg(any(test, fuzzing, debug_assertions))]
 use crate::sync::Mutex;
@@ -104,10 +103,38 @@ enum InboundHTLCRemovalReason {
        Fulfill(PaymentPreimage),
 }
 
+/// Represents the resolution status of an inbound HTLC.
+#[derive(Clone)]
+enum InboundHTLCResolution {
+       /// Resolved implies the action we must take with the inbound HTLC has already been determined,
+       /// i.e., we already know whether it must be failed back or forwarded.
+       //
+       // TODO: Once this variant is removed, we should also clean up
+       // [`MonitorRestoreUpdates::accepted_htlcs`] as the path will be unreachable.
+       Resolved {
+               pending_htlc_status: PendingHTLCStatus,
+       },
+       /// Pending implies we will attempt to resolve the inbound HTLC once it has been fully committed
+       /// to by both sides of the channel, i.e., once a `revoke_and_ack` has been processed by both
+       /// nodes for the state update in which it was proposed.
+       Pending {
+               update_add_htlc: msgs::UpdateAddHTLC,
+       },
+}
+
+impl_writeable_tlv_based_enum!(InboundHTLCResolution,
+       (0, Resolved) => {
+               (0, pending_htlc_status, required),
+       },
+       (2, Pending) => {
+               (0, update_add_htlc, required),
+       };
+);
+
 enum InboundHTLCState {
        /// Offered by remote, to be included in next local commitment tx. I.e., the remote sent an
        /// update_add_htlc message for this HTLC.
-       RemoteAnnounced(PendingHTLCStatus),
+       RemoteAnnounced(InboundHTLCResolution),
        /// Included in a received commitment_signed message (implying we've
        /// revoke_and_ack'd it), but the remote hasn't yet revoked their previous
        /// state (see the example below). We have not yet included this HTLC in a
@@ -137,13 +164,13 @@ enum InboundHTLCState {
        /// Implies AwaitingRemoteRevoke.
        ///
        /// [BOLT #2]: https://github.com/lightning/bolts/blob/master/02-peer-protocol.md
-       AwaitingRemoteRevokeToAnnounce(PendingHTLCStatus),
+       AwaitingRemoteRevokeToAnnounce(InboundHTLCResolution),
        /// Included in a received commitment_signed message (implying we've revoke_and_ack'd it).
        /// We have also included this HTLC in our latest commitment_signed and are now just waiting
        /// on the remote's revoke_and_ack to make this HTLC an irrevocable part of the state of the
        /// channel (before it can then get forwarded and/or removed).
        /// Implies AwaitingRemoteRevoke.
-       AwaitingAnnouncedRemoteRevoke(PendingHTLCStatus),
+       AwaitingAnnouncedRemoteRevoke(InboundHTLCResolution),
        Committed,
        /// Removed by us and a new commitment_signed was sent (if we were AwaitingRemoteRevoke when we
        /// created it we would have put it in the holding cell instead). When they next revoke_and_ack
@@ -158,6 +185,72 @@ enum InboundHTLCState {
        LocalRemoved(InboundHTLCRemovalReason),
 }
 
+/// Exposes the state of pending inbound HTLCs.
+///
+/// At a high level, an HTLC being forwarded from one Lightning node to another Lightning node goes
+/// through the following states in the state machine:
+/// - Announced for addition by the originating node through the update_add_htlc message.
+/// - Added to the commitment transaction of the receiving node and originating node in turn
+///   through the exchange of commitment_signed and revoke_and_ack messages.
+/// - Announced for resolution (fulfillment or failure) by the receiving node through either one of
+///   the update_fulfill_htlc, update_fail_htlc, and update_fail_malformed_htlc messages.
+/// - Removed from the commitment transaction of the originating node and receiving node in turn
+///   through the exchange of commitment_signed and revoke_and_ack messages.
+///
+/// This can be used to inspect what next message an HTLC is waiting for to advance its state.
+#[derive(Clone, Debug, PartialEq)]
+pub enum InboundHTLCStateDetails {
+       /// We have added this HTLC in our commitment transaction by receiving commitment_signed and
+       /// returning revoke_and_ack. We are awaiting the appropriate revoke_and_ack's from the remote
+       /// before this HTLC is included on the remote commitment transaction.
+       AwaitingRemoteRevokeToAdd,
+       /// This HTLC has been included in the commitment_signed and revoke_and_ack messages on both sides
+       /// and is included in both commitment transactions.
+       ///
+       /// This HTLC is now safe to either forward or be claimed as a payment by us. The HTLC will
+       /// remain in this state until the forwarded upstream HTLC has been resolved and we resolve this
+       /// HTLC correspondingly, or until we claim it as a payment. If it is part of a multipart
+       /// payment, it will only be claimed together with other required parts.
+       Committed,
+       /// We have received the preimage for this HTLC and it is being removed by fulfilling it with
+       /// update_fulfill_htlc. This HTLC is still on both commitment transactions, but we are awaiting
+       /// the appropriate revoke_and_ack's from the remote before this HTLC is removed from the remote
+       /// commitment transaction after update_fulfill_htlc.
+       AwaitingRemoteRevokeToRemoveFulfill,
+       /// The HTLC is being removed by failing it with update_fail_htlc or update_fail_malformed_htlc.
+       /// This HTLC is still on both commitment transactions, but we are awaiting the appropriate
+       /// revoke_and_ack's from the remote before this HTLC is removed from the remote commitment
+       /// transaction.
+       AwaitingRemoteRevokeToRemoveFail,
+}
+
+impl From<&InboundHTLCState> for Option<InboundHTLCStateDetails> {
+       fn from(state: &InboundHTLCState) -> Option<InboundHTLCStateDetails> {
+               match state {
+                       InboundHTLCState::RemoteAnnounced(_) => None,
+                       InboundHTLCState::AwaitingRemoteRevokeToAnnounce(_) =>
+                               Some(InboundHTLCStateDetails::AwaitingRemoteRevokeToAdd),
+                       InboundHTLCState::AwaitingAnnouncedRemoteRevoke(_) =>
+                               Some(InboundHTLCStateDetails::AwaitingRemoteRevokeToAdd),
+                       InboundHTLCState::Committed =>
+                               Some(InboundHTLCStateDetails::Committed),
+                       InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(_)) =>
+                               Some(InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFail),
+                       InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailMalformed(_)) =>
+                               Some(InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFail),
+                       InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(_)) =>
+                               Some(InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFulfill),
+               }
+       }
+}
+
+impl_writeable_tlv_based_enum_upgradable!(InboundHTLCStateDetails,
+       (0, AwaitingRemoteRevokeToAdd) => {},
+       (2, Committed) => {},
+       (4, AwaitingRemoteRevokeToRemoveFulfill) => {},
+       (6, AwaitingRemoteRevokeToRemoveFail) => {};
+);
+
 struct InboundHTLCOutput {
        htlc_id: u64,
        amount_msat: u64,
@@ -166,6 +259,53 @@ struct InboundHTLCOutput {
        state: InboundHTLCState,
 }
 
+/// Exposes details around pending inbound HTLCs.
+#[derive(Clone, Debug, PartialEq)]
+pub struct InboundHTLCDetails {
+       /// The HTLC ID.
+       /// The IDs are incremented by 1 starting from 0 for each offered HTLC.
+       /// They are unique per channel and inbound/outbound direction, unless an HTLC was only announced
+       /// and not part of any commitment transaction.
+       pub htlc_id: u64,
+       /// The amount in msat.
+       pub amount_msat: u64,
+       /// The block height at which this HTLC expires.
+       pub cltv_expiry: u32,
+       /// The payment hash.
+       pub payment_hash: PaymentHash,
+       /// The state of the HTLC in the state machine.
+       ///
+       /// Determines on which commitment transactions the HTLC is included and what message the HTLC is
+       /// waiting for to advance to the next state.
+       ///
+       /// See [`InboundHTLCStateDetails`] for information on the specific states.
+       ///
+       /// LDK will always fill this field in, but when downgrading to prior versions of LDK, new
+       /// states may result in `None` here.
+       pub state: Option<InboundHTLCStateDetails>,
+       /// Whether the HTLC has an output below the local dust limit. If so, the output will be trimmed
+       /// from the local commitment transaction and added to the commitment transaction fee.
+       /// For non-anchor channels, this takes into account the cost of the second-stage HTLC
+       /// transactions as well.
+       ///
+       /// When the local commitment transaction is broadcasted as part of a unilateral closure,
+       /// the value of this HTLC will therefore not be claimable but instead burned as a transaction
+       /// fee.
+       ///
+       /// Note that dust limits are specific to each party. An HTLC can be dust for the local
+       /// commitment transaction but not for the counterparty's commitment transaction and vice versa.
+       pub is_dust: bool,
+}
+
+impl_writeable_tlv_based!(InboundHTLCDetails, {
+       (0, htlc_id, required),
+       (2, amount_msat, required),
+       (4, cltv_expiry, required),
+       (6, payment_hash, required),
+       (7, state, upgradable_option),
+       (8, is_dust, required),
+});
+
 #[cfg_attr(test, derive(Clone, Debug, PartialEq))]
 enum OutboundHTLCState {
        /// Added by us and included in a commitment_signed (if we were AwaitingRemoteRevoke when we
@@ -199,6 +339,72 @@ enum OutboundHTLCState {
        AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome),
 }
 
+/// Exposes the state of pending outbound HTLCs.
+///
+/// At a high level, an HTLC being forwarded from one Lightning node to another Lightning node goes
+/// through the following states in the state machine:
+/// - Announced for addition by the originating node through the update_add_htlc message.
+/// - Added to the commitment transaction of the receiving node and originating node in turn
+///   through the exchange of commitment_signed and revoke_and_ack messages.
+/// - Announced for resolution (fulfillment or failure) by the receiving node through either one of
+///   the update_fulfill_htlc, update_fail_htlc, and update_fail_malformed_htlc messages.
+/// - Removed from the commitment transaction of the originating node and receiving node in turn
+///   through the exchange of commitment_signed and revoke_and_ack messages.
+///
+/// This can be used to inspect what next message an HTLC is waiting for to advance its state.
+#[derive(Clone, Debug, PartialEq)]
+pub enum OutboundHTLCStateDetails {
+       /// We are awaiting the appropriate revoke_and_ack's from the remote before the HTLC is added
+       /// on the remote's commitment transaction after update_add_htlc.
+       AwaitingRemoteRevokeToAdd,
+       /// The HTLC has been added to the remote's commitment transaction by sending commitment_signed
+       /// and receiving revoke_and_ack in return.
+       ///
+       /// The HTLC will remain in this state until the remote node resolves the HTLC, or until we
+       /// unilaterally close the channel due to a timeout with an uncooperative remote node.
+       Committed,
+       /// The HTLC has been fulfilled successfully by the remote with a preimage in update_fulfill_htlc,
+       /// and we removed the HTLC from our commitment transaction by receiving commitment_signed and
+       /// returning revoke_and_ack. We are awaiting the appropriate revoke_and_ack's from the remote
+       /// for the removal from its commitment transaction.
+       AwaitingRemoteRevokeToRemoveSuccess,
+       /// The HTLC has been failed by the remote with update_fail_htlc or update_fail_malformed_htlc,
+       /// and we removed the HTLC from our commitment transaction by receiving commitment_signed and
+       /// returning revoke_and_ack. We are awaiting the appropriate revoke_and_ack's from the remote
+       /// for the removal from its commitment transaction.
+       AwaitingRemoteRevokeToRemoveFailure,
+}
+
+impl From<&OutboundHTLCState> for OutboundHTLCStateDetails {
+       fn from(state: &OutboundHTLCState) -> OutboundHTLCStateDetails {
+               match state {
+                       OutboundHTLCState::LocalAnnounced(_) =>
+                               OutboundHTLCStateDetails::AwaitingRemoteRevokeToAdd,
+                       OutboundHTLCState::Committed =>
+                               OutboundHTLCStateDetails::Committed,
+                       // RemoteRemoved states are ignored as the state is transient and the remote has not committed to
+                       // the state yet.
+                       OutboundHTLCState::RemoteRemoved(_) =>
+                               OutboundHTLCStateDetails::Committed,
+                       OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_)) =>
+                               OutboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveSuccess,
+                       OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Failure(_)) =>
+                               OutboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFailure,
+                       OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_)) =>
+                               OutboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveSuccess,
+                       OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Failure(_)) =>
+                               OutboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFailure,
+               }
+       }
+}
+
+impl_writeable_tlv_based_enum_upgradable!(OutboundHTLCStateDetails,
+       (0, AwaitingRemoteRevokeToAdd) => {},
+       (2, Committed) => {},
+       (4, AwaitingRemoteRevokeToRemoveSuccess) => {},
+       (6, AwaitingRemoteRevokeToRemoveFailure) => {};
+);
+
 #[derive(Clone)]
 #[cfg_attr(test, derive(Debug, PartialEq))]
 enum OutboundHTLCOutcome {
@@ -237,6 +443,58 @@ struct OutboundHTLCOutput {
        skimmed_fee_msat: Option<u64>,
 }
 
+/// Exposes details around pending outbound HTLCs.
+#[derive(Clone, Debug, PartialEq)]
+pub struct OutboundHTLCDetails {
+       /// The HTLC ID.
+       /// The IDs are incremented by 1 starting from 0 for each offered HTLC.
+       /// They are unique per channel and inbound/outbound direction, unless an HTLC was only announced
+       /// and not part of any commitment transaction.
+       ///
+       /// Not present when we are awaiting a remote revocation and the HTLC is not added yet.
+       pub htlc_id: Option<u64>,
+       /// The amount in msat.
+       pub amount_msat: u64,
+       /// The block height at which this HTLC expires.
+       pub cltv_expiry: u32,
+       /// The payment hash.
+       pub payment_hash: PaymentHash,
+       /// The state of the HTLC in the state machine.
+       ///
+       /// Determines on which commitment transactions the HTLC is included and what message the HTLC is
+       /// waiting for to advance to the next state.
+       ///
+       /// See [`OutboundHTLCStateDetails`] for information on the specific states.
+       ///
+       /// LDK will always fill this field in, but when downgrading to prior versions of LDK, new
+       /// states may result in `None` here.
+       pub state: Option<OutboundHTLCStateDetails>,
+       /// The extra fee being skimmed off the top of this HTLC.
+       pub skimmed_fee_msat: Option<u64>,
+       /// Whether the HTLC has an output below the local dust limit. If so, the output will be trimmed
+       /// from the local commitment transaction and added to the commitment transaction fee.
+       /// For non-anchor channels, this takes into account the cost of the second-stage HTLC
+       /// transactions as well.
+       ///
+       /// When the local commitment transaction is broadcasted as part of a unilateral closure,
+       /// the value of this HTLC will therefore not be claimable but instead burned as a transaction
+       /// fee.
+       ///
+       /// Note that dust limits are specific to each party. An HTLC can be dust for the local
+       /// commitment transaction but not for the counterparty's commitment transaction and vice versa.
+       pub is_dust: bool,
+}
+
+impl_writeable_tlv_based!(OutboundHTLCDetails, {
+       (0, htlc_id, required),
+       (2, amount_msat, required),
+       (4, cltv_expiry, required),
+       (6, payment_hash, required),
+       (7, state, upgradable_option),
+       (8, skimmed_fee_msat, required),
+       (10, is_dust, required),
+});
+
 /// See AwaitingRemoteRevoke ChannelState for more info
 #[cfg_attr(test, derive(Clone, Debug, PartialEq))]
 enum HTLCUpdateAwaitingACK {
@@ -267,7 +525,7 @@ enum HTLCUpdateAwaitingACK {
 }
 
 macro_rules! define_state_flags {
-       ($flag_type_doc: expr, $flag_type: ident, [$(($flag_doc: expr, $flag: ident, $value: expr)),+], $extra_flags: expr) => {
+       ($flag_type_doc: expr, $flag_type: ident, [$(($flag_doc: expr, $flag: ident, $value: expr, $get: ident, $set: ident, $clear: ident)),+], $extra_flags: expr) => {
                #[doc = $flag_type_doc]
                #[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Eq)]
                struct $flag_type(u32);
@@ -296,15 +554,18 @@ macro_rules! define_state_flags {
 
                        #[allow(unused)]
                        fn is_empty(&self) -> bool { self.0 == 0 }
-
                        #[allow(unused)]
                        fn is_set(&self, flag: Self) -> bool { *self & flag == flag }
+                       #[allow(unused)]
+                       fn set(&mut self, flag: Self) { *self |= flag }
+                       #[allow(unused)]
+                       fn clear(&mut self, flag: Self) -> Self { self.0 &= !flag.0; *self }
                }
 
-               impl core::ops::Not for $flag_type {
-                       type Output = Self;
-                       fn not(self) -> Self::Output { Self(!self.0) }
-               }
+               $(
+                       define_state_flags!($flag_type, Self::$flag, $get, $set, $clear);
+               )*
+
                impl core::ops::BitOr for $flag_type {
                        type Output = Self;
                        fn bitor(self, rhs: Self) -> Self::Output { Self(self.0 | rhs.0) }
@@ -323,8 +584,28 @@ macro_rules! define_state_flags {
        ($flag_type_doc: expr, $flag_type: ident, $flags: tt) => {
                define_state_flags!($flag_type_doc, $flag_type, $flags, 0);
        };
+       ($flag_type: ident, $flag: expr, $get: ident, $set: ident, $clear: ident) => {
+               impl $flag_type {
+                       #[allow(unused)]
+                       fn $get(&self) -> bool { self.is_set($flag_type::new() | $flag) }
+                       #[allow(unused)]
+                       fn $set(&mut self) { self.set($flag_type::new() | $flag) }
+                       #[allow(unused)]
+                       fn $clear(&mut self) -> Self { self.clear($flag_type::new() | $flag) }
+               }
+       };
        ($flag_type_doc: expr, FUNDED_STATE, $flag_type: ident, $flags: tt) => {
                define_state_flags!($flag_type_doc, $flag_type, $flags, FundedStateFlags::ALL.0);
+
+               define_state_flags!($flag_type, FundedStateFlags::PEER_DISCONNECTED,
+                       is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected);
+               define_state_flags!($flag_type, FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS,
+                       is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress);
+               define_state_flags!($flag_type, FundedStateFlags::REMOTE_SHUTDOWN_SENT,
+                       is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent);
+               define_state_flags!($flag_type, FundedStateFlags::LOCAL_SHUTDOWN_SENT,
+                       is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent);
+
                impl core::ops::BitOr<FundedStateFlags> for $flag_type {
                        type Output = Self;
                        fn bitor(self, rhs: FundedStateFlags) -> Self::Output { Self(self.0 | rhs.0) }
@@ -371,15 +652,19 @@ define_state_flags!(
        "Flags that apply to all [`ChannelState`] variants in which the channel is funded.",
        FundedStateFlags, [
                ("Indicates the remote side is considered \"disconnected\" and no updates are allowed \
-                       until after we've done a `channel_reestablish` dance.", PEER_DISCONNECTED, state_flags::PEER_DISCONNECTED),
+                       until after we've done a `channel_reestablish` dance.", PEER_DISCONNECTED, state_flags::PEER_DISCONNECTED,
+                       is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected),
                ("Indicates the user has told us a `ChannelMonitor` update is pending async persistence \
                        somewhere and we should pause sending any outbound messages until they've managed to \
-                       complete it.", MONITOR_UPDATE_IN_PROGRESS, state_flags::MONITOR_UPDATE_IN_PROGRESS),
+                       complete it.", MONITOR_UPDATE_IN_PROGRESS, state_flags::MONITOR_UPDATE_IN_PROGRESS,
+                       is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress),
                ("Indicates we received a `shutdown` message from the remote end. If set, they may not add \
                        any new HTLCs to the channel, and we are expected to respond with our own `shutdown` \
-                       message when possible.", REMOTE_SHUTDOWN_SENT, state_flags::REMOTE_SHUTDOWN_SENT),
+                       message when possible.", REMOTE_SHUTDOWN_SENT, state_flags::REMOTE_SHUTDOWN_SENT,
+                       is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent),
                ("Indicates we sent a `shutdown` message. At this point, we may not add any new HTLCs to \
-                       the channel.", LOCAL_SHUTDOWN_SENT, state_flags::LOCAL_SHUTDOWN_SENT)
+                       the channel.", LOCAL_SHUTDOWN_SENT, state_flags::LOCAL_SHUTDOWN_SENT,
+                       is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent)
        ]
 );
 
@@ -387,9 +672,9 @@ define_state_flags!(
        "Flags that only apply to [`ChannelState::NegotiatingFunding`].",
        NegotiatingFundingFlags, [
                ("Indicates we have (or are prepared to) send our `open_channel`/`accept_channel` message.",
-                       OUR_INIT_SENT, state_flags::OUR_INIT_SENT),
+                       OUR_INIT_SENT, state_flags::OUR_INIT_SENT, is_our_init_sent, set_our_init_sent, clear_our_init_sent),
                ("Indicates we have received their `open_channel`/`accept_channel` message.",
-                       THEIR_INIT_SENT, state_flags::THEIR_INIT_SENT)
+                       THEIR_INIT_SENT, state_flags::THEIR_INIT_SENT, is_their_init_sent, set_their_init_sent, clear_their_init_sent)
        ]
 );
 
@@ -398,13 +683,16 @@ define_state_flags!(
        FUNDED_STATE, AwaitingChannelReadyFlags, [
                ("Indicates they sent us a `channel_ready` message. Once both `THEIR_CHANNEL_READY` and \
                        `OUR_CHANNEL_READY` are set, our state moves on to `ChannelReady`.",
-                       THEIR_CHANNEL_READY, state_flags::THEIR_CHANNEL_READY),
+                       THEIR_CHANNEL_READY, state_flags::THEIR_CHANNEL_READY,
+                       is_their_channel_ready, set_their_channel_ready, clear_their_channel_ready),
                ("Indicates we sent them a `channel_ready` message. Once both `THEIR_CHANNEL_READY` and \
                        `OUR_CHANNEL_READY` are set, our state moves on to `ChannelReady`.",
-                       OUR_CHANNEL_READY, state_flags::OUR_CHANNEL_READY),
+                       OUR_CHANNEL_READY, state_flags::OUR_CHANNEL_READY,
+                       is_our_channel_ready, set_our_channel_ready, clear_our_channel_ready),
                ("Indicates the channel was funded in a batch and the broadcast of the funding transaction \
                        is being held until all channels in the batch have received `funding_signed` and have \
-                       their monitors persisted.", WAITING_FOR_BATCH, state_flags::WAITING_FOR_BATCH)
+                       their monitors persisted.", WAITING_FOR_BATCH, state_flags::WAITING_FOR_BATCH,
+                       is_waiting_for_batch, set_waiting_for_batch, clear_waiting_for_batch)
        ]
 );
 
@@ -415,10 +703,13 @@ define_state_flags!(
                        `revoke_and_ack` message. During this period, we can't generate new `commitment_signed` \
                        messages as we'd be unable to determine which HTLCs they included in their `revoke_and_ack` \
                        implicit ACK, so instead we have to hold them away temporarily to be sent later.",
-                       AWAITING_REMOTE_REVOKE, state_flags::AWAITING_REMOTE_REVOKE)
+                       AWAITING_REMOTE_REVOKE, state_flags::AWAITING_REMOTE_REVOKE,
+                       is_awaiting_remote_revoke, set_awaiting_remote_revoke, clear_awaiting_remote_revoke)
        ]
 );
 
+// Note that the order of this enum is implicitly defined by where each variant is placed. Take this
+// into account when introducing new states and update `test_channel_state_order` accordingly.
 #[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Eq)]
 enum ChannelState {
        /// We are negotiating the parameters required for the channel prior to funding it.
@@ -439,12 +730,12 @@ enum ChannelState {
 }
 
 macro_rules! impl_state_flag {
-       ($get: ident, $set: ident, $clear: ident, $state_flag: expr, [$($state: ident),+]) => {
+       ($get: ident, $set: ident, $clear: ident, [$($state: ident),+]) => {
                #[allow(unused)]
                fn $get(&self) -> bool {
                        match self {
                                $(
-                                       ChannelState::$state(flags) => flags.is_set($state_flag.into()),
+                                       ChannelState::$state(flags) => flags.$get(),
                                )*
                                _ => false,
                        }
@@ -453,7 +744,7 @@ macro_rules! impl_state_flag {
                fn $set(&mut self) {
                        match self {
                                $(
-                                       ChannelState::$state(flags) => *flags |= $state_flag,
+                                       ChannelState::$state(flags) => flags.$set(),
                                )*
                                _ => debug_assert!(false, "Attempted to set flag on unexpected ChannelState"),
                        }
@@ -462,17 +753,17 @@ macro_rules! impl_state_flag {
                fn $clear(&mut self) {
                        match self {
                                $(
-                                       ChannelState::$state(flags) => *flags &= !($state_flag),
+                                       ChannelState::$state(flags) => { let _ = flags.$clear(); },
                                )*
                                _ => debug_assert!(false, "Attempted to clear flag on unexpected ChannelState"),
                        }
                }
        };
-       ($get: ident, $set: ident, $clear: ident, $state_flag: expr, FUNDED_STATES) => {
-               impl_state_flag!($get, $set, $clear, $state_flag, [AwaitingChannelReady, ChannelReady]);
+       ($get: ident, $set: ident, $clear: ident, FUNDED_STATES) => {
+               impl_state_flag!($get, $set, $clear, [AwaitingChannelReady, ChannelReady]);
        };
-       ($get: ident, $set: ident, $clear: ident, $state_flag: expr, $state: ident) => {
-               impl_state_flag!($get, $set, $clear, $state_flag, [$state]);
+       ($get: ident, $set: ident, $clear: ident, $state: ident) => {
+               impl_state_flag!($get, $set, $clear, [$state]);
        };
 }
 
@@ -523,35 +814,27 @@ impl ChannelState {
                }
        }
 
-       fn should_force_holding_cell(&self) -> bool {
+       fn can_generate_new_commitment(&self) -> bool {
                match self {
                        ChannelState::ChannelReady(flags) =>
-                               flags.is_set(ChannelReadyFlags::AWAITING_REMOTE_REVOKE) ||
-                                       flags.is_set(FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS.into()) ||
-                                       flags.is_set(FundedStateFlags::PEER_DISCONNECTED.into()),
+                               !flags.is_set(ChannelReadyFlags::AWAITING_REMOTE_REVOKE) &&
+                                       !flags.is_set(FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS.into()) &&
+                                       !flags.is_set(FundedStateFlags::PEER_DISCONNECTED.into()),
                        _ => {
-                               debug_assert!(false, "The holding cell is only valid within ChannelReady");
+                               debug_assert!(false, "Can only generate new commitment within ChannelReady");
                                false
                        },
                }
        }
 
-       impl_state_flag!(is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected,
-               FundedStateFlags::PEER_DISCONNECTED, FUNDED_STATES);
-       impl_state_flag!(is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress,
-               FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS, FUNDED_STATES);
-       impl_state_flag!(is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent,
-               FundedStateFlags::LOCAL_SHUTDOWN_SENT, FUNDED_STATES);
-       impl_state_flag!(is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent,
-               FundedStateFlags::REMOTE_SHUTDOWN_SENT, FUNDED_STATES);
-       impl_state_flag!(is_our_channel_ready, set_our_channel_ready, clear_our_channel_ready,
-               AwaitingChannelReadyFlags::OUR_CHANNEL_READY, AwaitingChannelReady);
-       impl_state_flag!(is_their_channel_ready, set_their_channel_ready, clear_their_channel_ready,
-               AwaitingChannelReadyFlags::THEIR_CHANNEL_READY, AwaitingChannelReady);
-       impl_state_flag!(is_waiting_for_batch, set_waiting_for_batch, clear_waiting_for_batch,
-               AwaitingChannelReadyFlags::WAITING_FOR_BATCH, AwaitingChannelReady);
-       impl_state_flag!(is_awaiting_remote_revoke, set_awaiting_remote_revoke, clear_awaiting_remote_revoke,
-               ChannelReadyFlags::AWAITING_REMOTE_REVOKE, ChannelReady);
+       impl_state_flag!(is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected, FUNDED_STATES);
+       impl_state_flag!(is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress, FUNDED_STATES);
+       impl_state_flag!(is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent, FUNDED_STATES);
+       impl_state_flag!(is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent, FUNDED_STATES);
+       impl_state_flag!(is_our_channel_ready, set_our_channel_ready, clear_our_channel_ready, AwaitingChannelReady);
+       impl_state_flag!(is_their_channel_ready, set_their_channel_ready, clear_their_channel_ready, AwaitingChannelReady);
+       impl_state_flag!(is_waiting_for_batch, set_waiting_for_batch, clear_waiting_for_batch, AwaitingChannelReady);
+       impl_state_flag!(is_awaiting_remote_revoke, set_awaiting_remote_revoke, clear_awaiting_remote_revoke, ChannelReady);
 }
 
 pub const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
@@ -732,8 +1015,8 @@ struct CommitmentStats<'a> {
        total_fee_sat: u64, // the total fee included in the transaction
        num_nondust_htlcs: usize,  // the number of HTLC outputs (dust HTLCs *non*-included)
        htlcs_included: Vec<(HTLCOutputInCommitment, Option<&'a HTLCSource>)>, // the list of HTLCs (dust HTLCs *included*) which were not ignored when building the transaction
-       local_balance_msat: u64, // local balance before fees but considering dust limits
-       remote_balance_msat: u64, // remote balance before fees but considering dust limits
+       local_balance_msat: u64, // local balance before fees *not* considering dust limits
+       remote_balance_msat: u64, // remote balance before fees *not* considering dust limits
        outbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful offered HTLCs since last commitment
        inbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful received HTLCs since last commitment
 }
@@ -788,6 +1071,7 @@ pub(super) struct MonitorRestoreUpdates {
        pub accepted_htlcs: Vec<(PendingHTLCInfo, u64)>,
        pub failed_htlcs: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
        pub finalized_claimed_htlcs: Vec<HTLCSource>,
+       pub pending_update_adds: Vec<msgs::UpdateAddHTLC>,
        pub funding_broadcastable: Option<Transaction>,
        pub channel_ready: Option<msgs::ChannelReady>,
        pub announcement_sigs: Option<msgs::AnnouncementSignatures>,
@@ -814,15 +1098,20 @@ pub(super) struct ReestablishResponses {
 /// The result of a shutdown that should be handled.
 #[must_use]
 pub(crate) struct ShutdownResult {
+       pub(crate) closure_reason: ClosureReason,
        /// A channel monitor update to apply.
-       pub(crate) monitor_update: Option<(PublicKey, OutPoint, ChannelMonitorUpdate)>,
+       pub(crate) monitor_update: Option<(PublicKey, OutPoint, ChannelId, ChannelMonitorUpdate)>,
        /// A list of dropped outbound HTLCs that can safely be failed backwards immediately.
        pub(crate) dropped_outbound_htlcs: Vec<(HTLCSource, PaymentHash, PublicKey, ChannelId)>,
        /// An unbroadcasted batch funding transaction id. The closure of this channel should be
        /// propagated to the remainder of the batch.
        pub(crate) unbroadcasted_batch_funding_txid: Option<Txid>,
        pub(crate) channel_id: ChannelId,
+       pub(crate) user_channel_id: u128,
+       pub(crate) channel_capacity_satoshis: u64,
        pub(crate) counterparty_node_id: PublicKey,
+       pub(crate) unbroadcasted_funding_tx: Option<Transaction>,
+       pub(crate) channel_funding_txo: Option<OutPoint>,
 }
 
 /// If the majority of the channels funds are to the fundee and the initiator holds only just
@@ -900,6 +1189,10 @@ impl_writeable_tlv_based!(PendingChannelMonitorUpdate, {
 pub(super) enum ChannelPhase<SP: Deref> where SP::Target: SignerProvider {
        UnfundedOutboundV1(OutboundV1Channel<SP>),
        UnfundedInboundV1(InboundV1Channel<SP>),
+       #[cfg(any(dual_funding, splicing))]
+       UnfundedOutboundV2(OutboundV2Channel<SP>),
+       #[cfg(any(dual_funding, splicing))]
+       UnfundedInboundV2(InboundV2Channel<SP>),
        Funded(Channel<SP>),
 }
 
@@ -912,6 +1205,10 @@ impl<'a, SP: Deref> ChannelPhase<SP> where
                        ChannelPhase::Funded(chan) => &chan.context,
                        ChannelPhase::UnfundedOutboundV1(chan) => &chan.context,
                        ChannelPhase::UnfundedInboundV1(chan) => &chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedOutboundV2(chan) => &chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedInboundV2(chan) => &chan.context,
                }
        }
 
@@ -920,6 +1217,10 @@ impl<'a, SP: Deref> ChannelPhase<SP> where
                        ChannelPhase::Funded(ref mut chan) => &mut chan.context,
                        ChannelPhase::UnfundedOutboundV1(ref mut chan) => &mut chan.context,
                        ChannelPhase::UnfundedInboundV1(ref mut chan) => &mut chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedOutboundV2(ref mut chan) => &mut chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedInboundV2(ref mut chan) => &mut chan.context,
                }
        }
 }
@@ -1018,6 +1319,7 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
        monitor_pending_forwards: Vec<(PendingHTLCInfo, u64)>,
        monitor_pending_failures: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
        monitor_pending_finalized_fulfills: Vec<HTLCSource>,
+       monitor_pending_update_adds: Vec<msgs::UpdateAddHTLC>,
 
        /// If we went to send a commitment update (ie some messages then [`msgs::CommitmentSigned`])
        /// but our signer (initially) refused to give us a signature, we should retry at some point in
@@ -1226,9 +1528,15 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
        // We track whether we already emitted a `ChannelReady` event.
        channel_ready_event_emitted: bool,
 
+       /// Some if we initiated to shut down the channel.
+       local_initiated_shutdown: Option<()>,
+
        /// The unique identifier used to re-derive the private key material for the channel through
        /// [`SignerProvider::derive_channel_signer`].
+       #[cfg(not(test))]
        channel_keys_id: [u8; 32],
+       #[cfg(test)]
+       pub channel_keys_id: [u8; 32],
 
        /// If we can't release a [`ChannelMonitorUpdate`] until some external action completes, we
        /// store it here and only release it to the `ChannelManager` once it asks for it.
@@ -1236,109 +1544,660 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
 }
 
 impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
-       /// Allowed in any state (including after shutdown)
-       pub fn get_update_time_counter(&self) -> u32 {
-               self.update_time_counter
-       }
+       fn new_for_inbound_channel<'a, ES: Deref, F: Deref, L: Deref>(
+               fee_estimator: &'a LowerBoundedFeeEstimator<F>,
+               entropy_source: &'a ES,
+               signer_provider: &'a SP,
+               counterparty_node_id: PublicKey,
+               their_features: &'a InitFeatures,
+               user_id: u128,
+               config: &'a UserConfig,
+               current_chain_height: u32,
+               logger: &'a L,
+               is_0conf: bool,
+               our_funding_satoshis: u64,
+               counterparty_pubkeys: ChannelPublicKeys,
+               channel_type: ChannelTypeFeatures,
+               holder_selected_channel_reserve_satoshis: u64,
+               msg_channel_reserve_satoshis: u64,
+               msg_push_msat: u64,
+               open_channel_fields: msgs::CommonOpenChannelFields,
+       ) -> Result<ChannelContext<SP>, ChannelError>
+               where
+                       ES::Target: EntropySource,
+                       F::Target: FeeEstimator,
+                       L::Target: Logger,
+                       SP::Target: SignerProvider,
+       {
+               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(open_channel_fields.temporary_channel_id));
+               let announced_channel = if (open_channel_fields.channel_flags & 1) == 1 { true } else { false };
 
-       pub fn get_latest_monitor_update_id(&self) -> u64 {
-               self.latest_monitor_update_id
-       }
+               let channel_value_satoshis = our_funding_satoshis.saturating_add(open_channel_fields.funding_satoshis);
 
-       pub fn should_announce(&self) -> bool {
-               self.config.announced_channel
-       }
+               let channel_keys_id = signer_provider.generate_channel_keys_id(true, channel_value_satoshis, user_id);
+               let holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
+               let pubkeys = holder_signer.pubkeys().clone();
 
-       pub fn is_outbound(&self) -> bool {
-               self.channel_transaction_parameters.is_outbound_from_holder
-       }
+               if config.channel_handshake_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
+                       return Err(ChannelError::Close(format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks. It must be greater than {}", config.channel_handshake_config.our_to_self_delay, BREAKDOWN_TIMEOUT)));
+               }
 
-       /// Gets the fee we'd want to charge for adding an HTLC output to this Channel
-       /// Allowed in any state (including after shutdown)
-       pub fn get_outbound_forwarding_fee_base_msat(&self) -> u32 {
-               self.config.options.forwarding_fee_base_msat
-       }
+               // Check sanity of message fields:
+               if channel_value_satoshis > config.channel_handshake_limits.max_funding_satoshis {
+                       return Err(ChannelError::Close(format!(
+                               "Per our config, funding must be at most {}. It was {}. Peer contribution: {}. Our contribution: {}",
+                               config.channel_handshake_limits.max_funding_satoshis, channel_value_satoshis,
+                               open_channel_fields.funding_satoshis, our_funding_satoshis)));
+               }
+               if channel_value_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
+                       return Err(ChannelError::Close(format!("Funding must be smaller than the total bitcoin supply. It was {}", channel_value_satoshis)));
+               }
+               if msg_channel_reserve_satoshis > channel_value_satoshis {
+                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must be no greater than channel_value_satoshis: {}", msg_channel_reserve_satoshis, channel_value_satoshis)));
+               }
+               let full_channel_value_msat = (channel_value_satoshis - msg_channel_reserve_satoshis) * 1000;
+               if msg_push_msat > full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("push_msat {} was larger than channel amount minus reserve ({})", msg_push_msat, full_channel_value_msat)));
+               }
+               if open_channel_fields.dust_limit_satoshis > channel_value_satoshis {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis {} was larger than channel_value_satoshis {}. Peer never wants payout outputs?", open_channel_fields.dust_limit_satoshis, channel_value_satoshis)));
+               }
+               if open_channel_fields.htlc_minimum_msat >= full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", open_channel_fields.htlc_minimum_msat, full_channel_value_msat)));
+               }
+               Channel::<SP>::check_remote_fee(&channel_type, fee_estimator, open_channel_fields.commitment_feerate_sat_per_1000_weight, None, &&logger)?;
 
-       /// Returns true if we've ever received a message from the remote end for this Channel
-       pub fn have_received_message(&self) -> bool {
-               self.channel_state > ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT)
-       }
+               let max_counterparty_selected_contest_delay = u16::min(config.channel_handshake_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
+               if open_channel_fields.to_self_delay > max_counterparty_selected_contest_delay {
+                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_counterparty_selected_contest_delay, open_channel_fields.to_self_delay)));
+               }
+               if open_channel_fields.max_accepted_htlcs < 1 {
+                       return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
+               }
+               if open_channel_fields.max_accepted_htlcs > MAX_HTLCS {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", open_channel_fields.max_accepted_htlcs, MAX_HTLCS)));
+               }
 
-       /// Returns true if this channel is fully established and not known to be closing.
-       /// Allowed in any state (including after shutdown)
-       pub fn is_usable(&self) -> bool {
-               matches!(self.channel_state, ChannelState::ChannelReady(_)) &&
-                       !self.channel_state.is_local_shutdown_sent() &&
-                       !self.channel_state.is_remote_shutdown_sent() &&
-                       !self.monitor_pending_channel_ready
-       }
+               // Now check against optional parameters as set by config...
+               if channel_value_satoshis < config.channel_handshake_limits.min_funding_satoshis {
+                       return Err(ChannelError::Close(format!("Funding satoshis ({}) is less than the user specified limit ({})", channel_value_satoshis, config.channel_handshake_limits.min_funding_satoshis)));
+               }
+               if open_channel_fields.htlc_minimum_msat > config.channel_handshake_limits.max_htlc_minimum_msat {
+                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", open_channel_fields.htlc_minimum_msat, config.channel_handshake_limits.max_htlc_minimum_msat)));
+               }
+               if open_channel_fields.max_htlc_value_in_flight_msat < config.channel_handshake_limits.min_max_htlc_value_in_flight_msat {
+                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", open_channel_fields.max_htlc_value_in_flight_msat, config.channel_handshake_limits.min_max_htlc_value_in_flight_msat)));
+               }
+               if msg_channel_reserve_satoshis > config.channel_handshake_limits.max_channel_reserve_satoshis {
+                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg_channel_reserve_satoshis, config.channel_handshake_limits.max_channel_reserve_satoshis)));
+               }
+               if open_channel_fields.max_accepted_htlcs < config.channel_handshake_limits.min_max_accepted_htlcs {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", open_channel_fields.max_accepted_htlcs, config.channel_handshake_limits.min_max_accepted_htlcs)));
+               }
+               if open_channel_fields.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", open_channel_fields.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
+               if open_channel_fields.dust_limit_satoshis >  MAX_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", open_channel_fields.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
 
-       /// shutdown state returns the state of the channel in its various stages of shutdown
-       pub fn shutdown_state(&self) -> ChannelShutdownState {
-               match self.channel_state {
-                       ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_) =>
-                               if self.channel_state.is_local_shutdown_sent() && !self.channel_state.is_remote_shutdown_sent() {
-                                       ChannelShutdownState::ShutdownInitiated
-                               } else if (self.channel_state.is_local_shutdown_sent() || self.channel_state.is_remote_shutdown_sent()) && !self.closing_negotiation_ready() {
-                                       ChannelShutdownState::ResolvingHTLCs
-                               } else if (self.channel_state.is_local_shutdown_sent() || self.channel_state.is_remote_shutdown_sent()) && self.closing_negotiation_ready() {
-                                       ChannelShutdownState::NegotiatingClosingFee
-                               } else {
-                                       ChannelShutdownState::NotShuttingDown
-                               },
-                       ChannelState::ShutdownComplete => ChannelShutdownState::ShutdownComplete,
-                       _ => ChannelShutdownState::NotShuttingDown,
+               // Convert things into internal flags and prep our state:
+
+               if config.channel_handshake_limits.force_announced_channel_preference {
+                       if config.channel_handshake_config.announced_channel != announced_channel {
+                               return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours".to_owned()));
+                       }
                }
-       }
 
-       fn closing_negotiation_ready(&self) -> bool {
-               let is_ready_to_close = match self.channel_state {
-                       ChannelState::AwaitingChannelReady(flags) =>
-                               flags & FundedStateFlags::ALL == FundedStateFlags::LOCAL_SHUTDOWN_SENT | FundedStateFlags::REMOTE_SHUTDOWN_SENT,
-                       ChannelState::ChannelReady(flags) =>
-                               flags == FundedStateFlags::LOCAL_SHUTDOWN_SENT | FundedStateFlags::REMOTE_SHUTDOWN_SENT,
-                       _ => false,
-               };
-               self.pending_inbound_htlcs.is_empty() &&
-                       self.pending_outbound_htlcs.is_empty() &&
-                       self.pending_update_fee.is_none() &&
-                       is_ready_to_close
-       }
+               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       // Protocol level safety check in place, although it should never happen because
+                       // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
+                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
+               if holder_selected_channel_reserve_satoshis * 1000 >= full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({})msats. Channel value is ({} - {})msats.", holder_selected_channel_reserve_satoshis * 1000, full_channel_value_msat, msg_push_msat)));
+               }
+               if msg_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       log_debug!(logger, "channel_reserve_satoshis ({}) is smaller than our dust limit ({}). We can broadcast stale states without any risk, implying this channel is very insecure for our counterparty.",
+                               msg_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
+               }
+               if holder_selected_channel_reserve_satoshis < open_channel_fields.dust_limit_satoshis {
+                       return Err(ChannelError::Close(format!("Dust limit ({}) too high for the channel reserve we require the remote to keep ({})", open_channel_fields.dust_limit_satoshis, holder_selected_channel_reserve_satoshis)));
+               }
 
-       /// Returns true if this channel is currently available for use. This is a superset of
-       /// is_usable() and considers things like the channel being temporarily disabled.
-       /// Allowed in any state (including after shutdown)
-       pub fn is_live(&self) -> bool {
-               self.is_usable() && !self.channel_state.is_peer_disconnected()
-       }
+               // check if the funder's amount for the initial commitment tx is sufficient
+               // for full fee payment plus a few HTLCs to ensure the channel will be useful.
+               let anchor_outputs_value = if channel_type.supports_anchors_zero_fee_htlc_tx() {
+                       ANCHOR_OUTPUT_VALUE_SATOSHI * 2
+               } else {
+                       0
+               };
+               let funders_amount_msat = open_channel_fields.funding_satoshis * 1000 - msg_push_msat;
+               let commitment_tx_fee = commit_tx_fee_msat(open_channel_fields.commitment_feerate_sat_per_1000_weight, MIN_AFFORDABLE_HTLC_COUNT, &channel_type) / 1000;
+               if (funders_amount_msat / 1000).saturating_sub(anchor_outputs_value) < commitment_tx_fee {
+                       return Err(ChannelError::Close(format!("Funding amount ({} sats) can't even pay fee for initial commitment transaction fee of {} sats.", (funders_amount_msat / 1000).saturating_sub(anchor_outputs_value), commitment_tx_fee)));
+               }
 
-       // Public utilities:
+               let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee - anchor_outputs_value;
+               // While it's reasonable for us to not meet the channel reserve initially (if they don't
+               // want to push much to us), our counterparty should always have more than our reserve.
+               if to_remote_satoshis < holder_selected_channel_reserve_satoshis {
+                       return Err(ChannelError::Close("Insufficient funding amount for initial reserve".to_owned()));
+               }
 
-       pub fn channel_id(&self) -> ChannelId {
-               self.channel_id
-       }
+               let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
+                       match &open_channel_fields.shutdown_scriptpubkey {
+                               &Some(ref script) => {
+                                       // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
+                                       if script.len() == 0 {
+                                               None
+                                       } else {
+                                               if !script::is_bolt2_compliant(&script, their_features) {
+                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)))
+                                               }
+                                               Some(script.clone())
+                                       }
+                               },
+                               // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
+                               &None => {
+                                       return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out".to_owned()));
+                               }
+                       }
+               } else { None };
 
-       // Return the `temporary_channel_id` used during channel establishment.
-       //
-       // Will return `None` for channels created prior to LDK version 0.0.115.
-       pub fn temporary_channel_id(&self) -> Option<ChannelId> {
-               self.temporary_channel_id
-       }
+               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
+                       match signer_provider.get_shutdown_scriptpubkey() {
+                               Ok(scriptpubkey) => Some(scriptpubkey),
+                               Err(_) => return Err(ChannelError::Close("Failed to get upfront shutdown scriptpubkey".to_owned())),
+                       }
+               } else { None };
 
-       pub fn minimum_depth(&self) -> Option<u32> {
-               self.minimum_depth
-       }
+               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
+                               return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+                       }
+               }
 
-       /// Gets the "user_id" value passed into the construction of this channel. It has no special
-       /// meaning and exists only to allow users to have a persistent identifier of a channel.
-       pub fn get_user_id(&self) -> u128 {
-               self.user_id
-       }
+               let destination_script = match signer_provider.get_destination_script(channel_keys_id) {
+                       Ok(script) => script,
+                       Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())),
+               };
 
-       /// Gets the channel's type
-       pub fn get_channel_type(&self) -> &ChannelTypeFeatures {
-               &self.channel_type
-       }
+               let mut secp_ctx = Secp256k1::new();
+               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
+
+               let minimum_depth = if is_0conf {
+                       Some(0)
+               } else {
+                       Some(cmp::max(config.channel_handshake_config.minimum_depth, 1))
+               };
+
+               let value_to_self_msat = our_funding_satoshis * 1000 + msg_push_msat;
+
+               // TODO(dual_funding): Checks for `funding_feerate_sat_per_1000_weight`?
+
+               let channel_context = ChannelContext {
+                       user_id,
+
+                       config: LegacyChannelConfig {
+                               options: config.channel_config.clone(),
+                               announced_channel,
+                               commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
+                       },
+
+                       prev_config: None,
+
+                       inbound_handshake_limits_override: None,
+
+                       temporary_channel_id: Some(open_channel_fields.temporary_channel_id),
+                       channel_id: open_channel_fields.temporary_channel_id,
+                       channel_state: ChannelState::NegotiatingFunding(
+                               NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT
+                       ),
+                       announcement_sigs_state: AnnouncementSigsState::NotSent,
+                       secp_ctx,
+
+                       latest_monitor_update_id: 0,
+
+                       holder_signer: ChannelSignerType::Ecdsa(holder_signer),
+                       shutdown_scriptpubkey,
+                       destination_script,
+
+                       cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       value_to_self_msat,
+
+                       pending_inbound_htlcs: Vec::new(),
+                       pending_outbound_htlcs: Vec::new(),
+                       holding_cell_htlc_updates: Vec::new(),
+                       pending_update_fee: None,
+                       holding_cell_update_fee: None,
+                       next_holder_htlc_id: 0,
+                       next_counterparty_htlc_id: 0,
+                       update_time_counter: 1,
+
+                       resend_order: RAACommitmentOrder::CommitmentFirst,
+
+                       monitor_pending_channel_ready: false,
+                       monitor_pending_revoke_and_ack: false,
+                       monitor_pending_commitment_signed: false,
+                       monitor_pending_forwards: Vec::new(),
+                       monitor_pending_failures: Vec::new(),
+                       monitor_pending_finalized_fulfills: Vec::new(),
+                       monitor_pending_update_adds: Vec::new(),
+
+                       signer_pending_commitment_update: false,
+                       signer_pending_funding: false,
+
+
+                       #[cfg(debug_assertions)]
+                       holder_max_commitment_tx_output: Mutex::new((value_to_self_msat, (channel_value_satoshis * 1000 - msg_push_msat).saturating_sub(value_to_self_msat))),
+                       #[cfg(debug_assertions)]
+                       counterparty_max_commitment_tx_output: Mutex::new((value_to_self_msat, (channel_value_satoshis * 1000 - msg_push_msat).saturating_sub(value_to_self_msat))),
+
+                       last_sent_closing_fee: None,
+                       pending_counterparty_closing_signed: None,
+                       expecting_peer_commitment_signed: false,
+                       closing_fee_limits: None,
+                       target_closing_feerate_sats_per_kw: None,
+
+                       funding_tx_confirmed_in: None,
+                       funding_tx_confirmation_height: 0,
+                       short_channel_id: None,
+                       channel_creation_height: current_chain_height,
+
+                       feerate_per_kw: open_channel_fields.commitment_feerate_sat_per_1000_weight,
+                       channel_value_satoshis,
+                       counterparty_dust_limit_satoshis: open_channel_fields.dust_limit_satoshis,
+                       holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
+                       counterparty_max_htlc_value_in_flight_msat: cmp::min(open_channel_fields.max_htlc_value_in_flight_msat, channel_value_satoshis * 1000),
+                       holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis, &config.channel_handshake_config),
+                       counterparty_selected_channel_reserve_satoshis: Some(msg_channel_reserve_satoshis),
+                       holder_selected_channel_reserve_satoshis,
+                       counterparty_htlc_minimum_msat: open_channel_fields.htlc_minimum_msat,
+                       holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
+                       counterparty_max_accepted_htlcs: open_channel_fields.max_accepted_htlcs,
+                       holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
+                       minimum_depth,
+
+                       counterparty_forwarding_info: None,
+
+                       channel_transaction_parameters: ChannelTransactionParameters {
+                               holder_pubkeys: pubkeys,
+                               holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
+                               is_outbound_from_holder: false,
+                               counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
+                                       selected_contest_delay: open_channel_fields.to_self_delay,
+                                       pubkeys: counterparty_pubkeys,
+                               }),
+                               funding_outpoint: None,
+                               channel_type_features: channel_type.clone()
+                       },
+                       funding_transaction: None,
+                       is_batch_funding: None,
+
+                       counterparty_cur_commitment_point: Some(open_channel_fields.first_per_commitment_point),
+                       counterparty_prev_commitment_point: None,
+                       counterparty_node_id,
+
+                       counterparty_shutdown_scriptpubkey,
+
+                       commitment_secrets: CounterpartyCommitmentSecrets::new(),
+
+                       channel_update_status: ChannelUpdateStatus::Enabled,
+                       closing_signed_in_flight: false,
+
+                       announcement_sigs: None,
+
+                       #[cfg(any(test, fuzzing))]
+                       next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+                       #[cfg(any(test, fuzzing))]
+                       next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
+
+                       workaround_lnd_bug_4006: None,
+                       sent_message_awaiting_response: None,
+
+                       latest_inbound_scid_alias: None,
+                       outbound_scid_alias: 0,
+
+                       channel_pending_event_emitted: false,
+                       channel_ready_event_emitted: false,
+
+                       #[cfg(any(test, fuzzing))]
+                       historical_inbound_htlc_fulfills: new_hash_set(),
+
+                       channel_type,
+                       channel_keys_id,
+
+                       local_initiated_shutdown: None,
+
+                       blocked_monitor_updates: Vec::new(),
+               };
+
+               Ok(channel_context)
+       }
+
+       fn new_for_outbound_channel<'a, ES: Deref, F: Deref>(
+               fee_estimator: &'a LowerBoundedFeeEstimator<F>,
+               entropy_source: &'a ES,
+               signer_provider: &'a SP,
+               counterparty_node_id: PublicKey,
+               their_features: &'a InitFeatures,
+               funding_satoshis: u64,
+               push_msat: u64,
+               user_id: u128,
+               config: &'a UserConfig,
+               current_chain_height: u32,
+               outbound_scid_alias: u64,
+               temporary_channel_id: Option<ChannelId>,
+               holder_selected_channel_reserve_satoshis: u64,
+               channel_keys_id: [u8; 32],
+               holder_signer: <SP::Target as SignerProvider>::EcdsaSigner,
+               pubkeys: ChannelPublicKeys,
+       ) -> Result<ChannelContext<SP>, APIError>
+               where
+                       ES::Target: EntropySource,
+                       F::Target: FeeEstimator,
+                       SP::Target: SignerProvider,
+       {
+               // This will be updated with the counterparty contribution if this is a dual-funded channel
+               let channel_value_satoshis = funding_satoshis;
+
+               let holder_selected_contest_delay = config.channel_handshake_config.our_to_self_delay;
+
+               if !their_features.supports_wumbo() && channel_value_satoshis > MAX_FUNDING_SATOSHIS_NO_WUMBO {
+                       return Err(APIError::APIMisuseError{err: format!("funding_value must not exceed {}, it was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, channel_value_satoshis)});
+               }
+               if channel_value_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
+                       return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than the total bitcoin supply, it was {}", channel_value_satoshis)});
+               }
+               let channel_value_msat = channel_value_satoshis * 1000;
+               if push_msat > channel_value_msat {
+                       return Err(APIError::APIMisuseError { err: format!("Push value ({}) was larger than channel_value ({})", push_msat, channel_value_msat) });
+               }
+               if holder_selected_contest_delay < BREAKDOWN_TIMEOUT {
+                       return Err(APIError::APIMisuseError {err: format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks", holder_selected_contest_delay)});
+               }
+
+               let channel_type = get_initial_channel_type(&config, their_features);
+               debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config)));
+
+               let (commitment_conf_target, anchor_outputs_value_msat)  = if channel_type.supports_anchors_zero_fee_htlc_tx() {
+                       (ConfirmationTarget::AnchorChannelFee, ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000)
+               } else {
+                       (ConfirmationTarget::NonAnchorChannelFee, 0)
+               };
+               let commitment_feerate = fee_estimator.bounded_sat_per_1000_weight(commitment_conf_target);
+
+               let value_to_self_msat = channel_value_satoshis * 1000 - push_msat;
+               let commitment_tx_fee = commit_tx_fee_msat(commitment_feerate, MIN_AFFORDABLE_HTLC_COUNT, &channel_type);
+               if value_to_self_msat.saturating_sub(anchor_outputs_value_msat) < commitment_tx_fee {
+                       return Err(APIError::APIMisuseError{ err: format!("Funding amount ({}) can't even pay fee for initial commitment transaction fee of {}.", value_to_self_msat / 1000, commitment_tx_fee / 1000) });
+               }
+
+               let mut secp_ctx = Secp256k1::new();
+               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
+
+               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
+                       match signer_provider.get_shutdown_scriptpubkey() {
+                               Ok(scriptpubkey) => Some(scriptpubkey),
+                               Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get shutdown scriptpubkey".to_owned()}),
+                       }
+               } else { None };
+
+               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
+                               return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
+                       }
+               }
+
+               let destination_script = match signer_provider.get_destination_script(channel_keys_id) {
+                       Ok(script) => script,
+                       Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get destination script".to_owned()}),
+               };
+
+               let temporary_channel_id = temporary_channel_id.unwrap_or_else(|| ChannelId::temporary_from_entropy_source(entropy_source));
+
+               Ok(Self {
+                       user_id,
+
+                       config: LegacyChannelConfig {
+                               options: config.channel_config.clone(),
+                               announced_channel: config.channel_handshake_config.announced_channel,
+                               commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
+                       },
+
+                       prev_config: None,
+
+                       inbound_handshake_limits_override: Some(config.channel_handshake_limits.clone()),
+
+                       channel_id: temporary_channel_id,
+                       temporary_channel_id: Some(temporary_channel_id),
+                       channel_state: ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT),
+                       announcement_sigs_state: AnnouncementSigsState::NotSent,
+                       secp_ctx,
+                       // We'll add our counterparty's `funding_satoshis` when we receive `accept_channel2`.
+                       channel_value_satoshis,
+
+                       latest_monitor_update_id: 0,
+
+                       holder_signer: ChannelSignerType::Ecdsa(holder_signer),
+                       shutdown_scriptpubkey,
+                       destination_script,
+
+                       cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       value_to_self_msat,
+
+                       pending_inbound_htlcs: Vec::new(),
+                       pending_outbound_htlcs: Vec::new(),
+                       holding_cell_htlc_updates: Vec::new(),
+                       pending_update_fee: None,
+                       holding_cell_update_fee: None,
+                       next_holder_htlc_id: 0,
+                       next_counterparty_htlc_id: 0,
+                       update_time_counter: 1,
+
+                       resend_order: RAACommitmentOrder::CommitmentFirst,
+
+                       monitor_pending_channel_ready: false,
+                       monitor_pending_revoke_and_ack: false,
+                       monitor_pending_commitment_signed: false,
+                       monitor_pending_forwards: Vec::new(),
+                       monitor_pending_failures: Vec::new(),
+                       monitor_pending_finalized_fulfills: Vec::new(),
+                       monitor_pending_update_adds: Vec::new(),
+
+                       signer_pending_commitment_update: false,
+                       signer_pending_funding: false,
+
+                       // We'll add our counterparty's `funding_satoshis` to these max commitment output assertions
+                       // when we receive `accept_channel2`.
+                       #[cfg(debug_assertions)]
+                       holder_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+                       #[cfg(debug_assertions)]
+                       counterparty_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+
+                       last_sent_closing_fee: None,
+                       pending_counterparty_closing_signed: None,
+                       expecting_peer_commitment_signed: false,
+                       closing_fee_limits: None,
+                       target_closing_feerate_sats_per_kw: None,
+
+                       funding_tx_confirmed_in: None,
+                       funding_tx_confirmation_height: 0,
+                       short_channel_id: None,
+                       channel_creation_height: current_chain_height,
+
+                       feerate_per_kw: commitment_feerate,
+                       counterparty_dust_limit_satoshis: 0,
+                       holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
+                       counterparty_max_htlc_value_in_flight_msat: 0,
+                       // We'll adjust this to include our counterparty's `funding_satoshis` when we
+                       // receive `accept_channel2`.
+                       holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis, &config.channel_handshake_config),
+                       counterparty_selected_channel_reserve_satoshis: None, // Filled in in accept_channel
+                       holder_selected_channel_reserve_satoshis,
+                       counterparty_htlc_minimum_msat: 0,
+                       holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
+                       counterparty_max_accepted_htlcs: 0,
+                       holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
+                       minimum_depth: None, // Filled in in accept_channel
+
+                       counterparty_forwarding_info: None,
+
+                       channel_transaction_parameters: ChannelTransactionParameters {
+                               holder_pubkeys: pubkeys,
+                               holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
+                               is_outbound_from_holder: true,
+                               counterparty_parameters: None,
+                               funding_outpoint: None,
+                               channel_type_features: channel_type.clone()
+                       },
+                       funding_transaction: None,
+                       is_batch_funding: None,
+
+                       counterparty_cur_commitment_point: None,
+                       counterparty_prev_commitment_point: None,
+                       counterparty_node_id,
+
+                       counterparty_shutdown_scriptpubkey: None,
+
+                       commitment_secrets: CounterpartyCommitmentSecrets::new(),
+
+                       channel_update_status: ChannelUpdateStatus::Enabled,
+                       closing_signed_in_flight: false,
+
+                       announcement_sigs: None,
+
+                       #[cfg(any(test, fuzzing))]
+                       next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+                       #[cfg(any(test, fuzzing))]
+                       next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
+
+                       workaround_lnd_bug_4006: None,
+                       sent_message_awaiting_response: None,
+
+                       latest_inbound_scid_alias: None,
+                       outbound_scid_alias,
+
+                       channel_pending_event_emitted: false,
+                       channel_ready_event_emitted: false,
+
+                       #[cfg(any(test, fuzzing))]
+                       historical_inbound_htlc_fulfills: new_hash_set(),
+
+                       channel_type,
+                       channel_keys_id,
+
+                       blocked_monitor_updates: Vec::new(),
+                       local_initiated_shutdown: None,
+               })
+       }
+
+       /// Allowed in any state (including after shutdown)
+       pub fn get_update_time_counter(&self) -> u32 {
+               self.update_time_counter
+       }
+
+       pub fn get_latest_monitor_update_id(&self) -> u64 {
+               self.latest_monitor_update_id
+       }
+
+       pub fn should_announce(&self) -> bool {
+               self.config.announced_channel
+       }
+
+       pub fn is_outbound(&self) -> bool {
+               self.channel_transaction_parameters.is_outbound_from_holder
+       }
+
+       /// Gets the fee we'd want to charge for adding an HTLC output to this Channel
+       /// Allowed in any state (including after shutdown)
+       pub fn get_outbound_forwarding_fee_base_msat(&self) -> u32 {
+               self.config.options.forwarding_fee_base_msat
+       }
+
+       /// Returns true if we've ever received a message from the remote end for this Channel
+       pub fn have_received_message(&self) -> bool {
+               self.channel_state > ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT)
+       }
+
+       /// Returns true if this channel is fully established and not known to be closing.
+       /// Allowed in any state (including after shutdown)
+       pub fn is_usable(&self) -> bool {
+               matches!(self.channel_state, ChannelState::ChannelReady(_)) &&
+                       !self.channel_state.is_local_shutdown_sent() &&
+                       !self.channel_state.is_remote_shutdown_sent() &&
+                       !self.monitor_pending_channel_ready
+       }
+
+       /// shutdown state returns the state of the channel in its various stages of shutdown
+       pub fn shutdown_state(&self) -> ChannelShutdownState {
+               match self.channel_state {
+                       ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_) =>
+                               if self.channel_state.is_local_shutdown_sent() && !self.channel_state.is_remote_shutdown_sent() {
+                                       ChannelShutdownState::ShutdownInitiated
+                               } else if (self.channel_state.is_local_shutdown_sent() || self.channel_state.is_remote_shutdown_sent()) && !self.closing_negotiation_ready() {
+                                       ChannelShutdownState::ResolvingHTLCs
+                               } else if (self.channel_state.is_local_shutdown_sent() || self.channel_state.is_remote_shutdown_sent()) && self.closing_negotiation_ready() {
+                                       ChannelShutdownState::NegotiatingClosingFee
+                               } else {
+                                       ChannelShutdownState::NotShuttingDown
+                               },
+                       ChannelState::ShutdownComplete => ChannelShutdownState::ShutdownComplete,
+                       _ => ChannelShutdownState::NotShuttingDown,
+               }
+       }
+
+       fn closing_negotiation_ready(&self) -> bool {
+               let is_ready_to_close = match self.channel_state {
+                       ChannelState::AwaitingChannelReady(flags) =>
+                               flags & FundedStateFlags::ALL == FundedStateFlags::LOCAL_SHUTDOWN_SENT | FundedStateFlags::REMOTE_SHUTDOWN_SENT,
+                       ChannelState::ChannelReady(flags) =>
+                               flags == FundedStateFlags::LOCAL_SHUTDOWN_SENT | FundedStateFlags::REMOTE_SHUTDOWN_SENT,
+                       _ => false,
+               };
+               self.pending_inbound_htlcs.is_empty() &&
+                       self.pending_outbound_htlcs.is_empty() &&
+                       self.pending_update_fee.is_none() &&
+                       is_ready_to_close
+       }
+
+       /// Returns true if this channel is currently available for use. This is a superset of
+       /// is_usable() and considers things like the channel being temporarily disabled.
+       /// Allowed in any state (including after shutdown)
+       pub fn is_live(&self) -> bool {
+               self.is_usable() && !self.channel_state.is_peer_disconnected()
+       }
+
+       // Public utilities:
+
+       pub fn channel_id(&self) -> ChannelId {
+               self.channel_id
+       }
+
+       // Return the `temporary_channel_id` used during channel establishment.
+       //
+       // Will return `None` for channels created prior to LDK version 0.0.115.
+       pub fn temporary_channel_id(&self) -> Option<ChannelId> {
+               self.temporary_channel_id
+       }
+
+       pub fn minimum_depth(&self) -> Option<u32> {
+               self.minimum_depth
+       }
+
+       /// Gets the "user_id" value passed into the construction of this channel. It has no special
+       /// meaning and exists only to allow users to have a persistent identifier of a channel.
+       pub fn get_user_id(&self) -> u128 {
+               self.user_id
+       }
+
+       /// Gets the channel's type
+       pub fn get_channel_type(&self) -> &ChannelTypeFeatures {
+               &self.channel_type
+       }
 
        /// Gets the channel's `short_channel_id`.
        ///
@@ -1728,13 +2587,13 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        }
                }
 
-               let mut value_to_self_msat: i64 = (self.value_to_self_msat - local_htlc_total_msat) as i64 + value_to_self_msat_offset;
+               let value_to_self_msat: i64 = (self.value_to_self_msat - local_htlc_total_msat) as i64 + value_to_self_msat_offset;
                assert!(value_to_self_msat >= 0);
                // Note that in case they have several just-awaiting-last-RAA fulfills in-progress (ie
                // AwaitingRemoteRevokeToRemove or AwaitingRemovedRemoteRevoke) we may have allowed them to
                // "violate" their reserve value by couting those against it. Thus, we have to convert
                // everything to i64 before subtracting as otherwise we can overflow.
-               let mut value_to_remote_msat: i64 = (self.channel_value_satoshis * 1000) as i64 - (self.value_to_self_msat as i64) - (remote_htlc_total_msat as i64) - value_to_self_msat_offset;
+               let value_to_remote_msat: i64 = (self.channel_value_satoshis * 1000) as i64 - (self.value_to_self_msat as i64) - (remote_htlc_total_msat as i64) - value_to_self_msat_offset;
                assert!(value_to_remote_msat >= 0);
 
                #[cfg(debug_assertions)]
@@ -1800,10 +2659,6 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                htlcs_included.sort_unstable_by_key(|h| h.0.transaction_output_index.unwrap());
                htlcs_included.append(&mut included_dust_htlcs);
 
-               // For the stats, trimmed-to-0 the value in msats accordingly
-               value_to_self_msat = if (value_to_self_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_self_msat };
-               value_to_remote_msat = if (value_to_remote_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_remote_msat };
-
                CommitmentStats {
                        tx,
                        feerate_per_kw,
@@ -1837,8 +2692,6 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
        /// will sign and send to our counterparty.
        /// If an Err is returned, it is a ChannelError::Close (for get_funding_created)
        fn build_remote_transaction_keys(&self) -> TxCreationKeys {
-               //TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we
-               //may see payments to it!
                let revocation_basepoint = &self.get_holder_pubkeys().revocation_basepoint;
                let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
                let counterparty_pubkeys = self.get_counterparty_pubkeys();
@@ -1876,7 +2729,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                if let Some(feerate) = outbound_feerate_update {
                        feerate_per_kw = cmp::max(feerate_per_kw, feerate);
                }
-               cmp::max(2530, feerate_per_kw * 1250 / 1000)
+               let feerate_plus_quarter = feerate_per_kw.checked_mul(1250).map(|v| v / 1000);
+               cmp::max(feerate_per_kw + 2530, feerate_plus_quarter.unwrap_or(u32::max_value()))
        }
 
        /// Get forwarding information for the counterparty.
@@ -1966,6 +2820,99 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                stats
        }
 
+       /// Returns information on all pending inbound HTLCs.
+       pub fn get_pending_inbound_htlc_details(&self) -> Vec<InboundHTLCDetails> {
+               let mut holding_cell_states = new_hash_map();
+               for holding_cell_update in self.holding_cell_htlc_updates.iter() {
+                       match holding_cell_update {
+                               HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
+                                       holding_cell_states.insert(
+                                               htlc_id,
+                                               InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFulfill,
+                                       );
+                               },
+                               HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
+                                       holding_cell_states.insert(
+                                               htlc_id,
+                                               InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFail,
+                                       );
+                               },
+                               HTLCUpdateAwaitingACK::FailMalformedHTLC { htlc_id, .. } => {
+                                       holding_cell_states.insert(
+                                               htlc_id,
+                                               InboundHTLCStateDetails::AwaitingRemoteRevokeToRemoveFail,
+                                       );
+                               },
+                               // Outbound HTLC.
+                               HTLCUpdateAwaitingACK::AddHTLC { .. } => {},
+                       }
+               }
+               let mut inbound_details = Vec::new();
+               let htlc_success_dust_limit = if self.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                       0
+               } else {
+                       let dust_buffer_feerate = self.get_dust_buffer_feerate(None) as u64;
+                       dust_buffer_feerate * htlc_success_tx_weight(self.get_channel_type()) / 1000
+               };
+               let holder_dust_limit_success_sat = htlc_success_dust_limit + self.holder_dust_limit_satoshis;
+               for htlc in self.pending_inbound_htlcs.iter() {
+                       if let Some(state_details) = (&htlc.state).into() {
+                               inbound_details.push(InboundHTLCDetails{
+                                       htlc_id: htlc.htlc_id,
+                                       amount_msat: htlc.amount_msat,
+                                       cltv_expiry: htlc.cltv_expiry,
+                                       payment_hash: htlc.payment_hash,
+                                       state: Some(holding_cell_states.remove(&htlc.htlc_id).unwrap_or(state_details)),
+                                       is_dust: htlc.amount_msat / 1000 < holder_dust_limit_success_sat,
+                               });
+                       }
+               }
+               inbound_details
+       }
+
+       /// Returns information on all pending outbound HTLCs.
+       pub fn get_pending_outbound_htlc_details(&self) -> Vec<OutboundHTLCDetails> {
+               let mut outbound_details = Vec::new();
+               let htlc_timeout_dust_limit = if self.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                       0
+               } else {
+                       let dust_buffer_feerate = self.get_dust_buffer_feerate(None) as u64;
+                       dust_buffer_feerate * htlc_success_tx_weight(self.get_channel_type()) / 1000
+               };
+               let holder_dust_limit_timeout_sat = htlc_timeout_dust_limit + self.holder_dust_limit_satoshis;
+               for htlc in self.pending_outbound_htlcs.iter() {
+                       outbound_details.push(OutboundHTLCDetails{
+                               htlc_id: Some(htlc.htlc_id),
+                               amount_msat: htlc.amount_msat,
+                               cltv_expiry: htlc.cltv_expiry,
+                               payment_hash: htlc.payment_hash,
+                               skimmed_fee_msat: htlc.skimmed_fee_msat,
+                               state: Some((&htlc.state).into()),
+                               is_dust: htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat,
+                       });
+               }
+               for holding_cell_update in self.holding_cell_htlc_updates.iter() {
+                       if let HTLCUpdateAwaitingACK::AddHTLC {
+                               amount_msat,
+                               cltv_expiry,
+                               payment_hash,
+                               skimmed_fee_msat,
+                               ..
+                       } = *holding_cell_update {
+                               outbound_details.push(OutboundHTLCDetails{
+                                       htlc_id: None,
+                                       amount_msat: amount_msat,
+                                       cltv_expiry: cltv_expiry,
+                                       payment_hash: payment_hash,
+                                       skimmed_fee_msat: skimmed_fee_msat,
+                                       state: Some(OutboundHTLCStateDetails::AwaitingRemoteRevokeToAdd),
+                                       is_dust: amount_msat / 1000 < holder_dust_limit_timeout_sat,
+                               });
+                       }
+               }
+               outbound_details
+       }
+
        /// Get the available balances, see [`AvailableBalances`]'s fields for more info.
        /// Doesn't bother handling the
        /// if-we-removed-it-already-but-haven't-fully-resolved-they-can-still-send-an-inbound-HTLC
@@ -2316,15 +3263,17 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                res
        }
 
-       fn if_unbroadcasted_funding<F, O>(&self, f: F) -> Option<O>
-               where F: Fn() -> Option<O> {
+       fn if_unbroadcasted_funding<F, O>(&self, f: F) -> Option<O> where F: Fn() -> Option<O> {
                match self.channel_state {
                        ChannelState::FundingNegotiated => f(),
-                       ChannelState::AwaitingChannelReady(flags) => if flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH) {
-                               f()
-                       } else {
-                               None
-                       },
+                       ChannelState::AwaitingChannelReady(flags) =>
+                               if flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH) ||
+                                       flags.is_set(FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS.into())
+                               {
+                                       f()
+                               } else {
+                                       None
+                               },
                        _ => None,
                }
        }
@@ -2359,7 +3308,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
        /// those explicitly stated to be allowed after shutdown completes, eg some simple getters).
        /// Also returns the list of payment_hashes for channels which we can safely fail backwards
        /// immediately (others we will have to allow to time out).
-       pub fn force_shutdown(&mut self, should_broadcast: bool) -> ShutdownResult {
+       pub fn force_shutdown(&mut self, should_broadcast: bool, closure_reason: ClosureReason) -> ShutdownResult {
                // Note that we MUST only generate a monitor update that indicates force-closure - we're
                // called during initialization prior to the chain_monitor in the encompassing ChannelManager
                // being fully configured in some cases. Thus, its likely any monitor events we generate will
@@ -2386,28 +3335,32 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        // funding transaction, don't return a funding txo (which prevents providing the
                        // monitor update to the user, even if we return one).
                        // See test_duplicate_chan_id and test_pre_lockin_no_chan_closed_update for more.
-                       let generate_monitor_update = match self.channel_state {
-                               ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_)|ChannelState::ShutdownComplete => true,
-                               _ => false,
-                       };
-                       if generate_monitor_update {
+                       if !self.channel_state.is_pre_funded_state() {
                                self.latest_monitor_update_id = CLOSED_CHANNEL_UPDATE_ID;
-                               Some((self.get_counterparty_node_id(), funding_txo, ChannelMonitorUpdate {
+                               Some((self.get_counterparty_node_id(), funding_txo, self.channel_id(), ChannelMonitorUpdate {
                                        update_id: self.latest_monitor_update_id,
+                                       counterparty_node_id: Some(self.counterparty_node_id),
                                        updates: vec![ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast }],
+                                       channel_id: Some(self.channel_id()),
                                }))
                        } else { None }
                } else { None };
                let unbroadcasted_batch_funding_txid = self.unbroadcasted_batch_funding_txid();
+               let unbroadcasted_funding_tx = self.unbroadcasted_funding();
 
                self.channel_state = ChannelState::ShutdownComplete;
                self.update_time_counter += 1;
                ShutdownResult {
+                       closure_reason,
                        monitor_update,
                        dropped_outbound_htlcs,
                        unbroadcasted_batch_funding_txid,
                        channel_id: self.channel_id,
+                       user_channel_id: self.user_id,
+                       channel_capacity_satoshis: self.channel_value_satoshis,
                        counterparty_node_id: self.counterparty_node_id,
+                       unbroadcasted_funding_tx,
+                       channel_funding_txo: self.get_funding_txo(),
                }
        }
 
@@ -2434,8 +3387,13 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                                        .ok();
 
                                if funding_signed.is_none() {
-                                       log_trace!(logger, "Counterparty commitment signature not available for funding_signed message; setting signer_pending_funding");
-                                       self.signer_pending_funding = true;
+                                       #[cfg(not(async_signing))] {
+                                               panic!("Failed to get signature for funding_signed");
+                                       }
+                                       #[cfg(async_signing)] {
+                                               log_trace!(logger, "Counterparty commitment signature not available for funding_signed message; setting signer_pending_funding");
+                                               self.signer_pending_funding = true;
+                                       }
                                } else if self.signer_pending_funding {
                                        log_trace!(logger, "Counterparty commitment signature available for funding_signed message; clearing signer_pending_funding");
                                        self.signer_pending_funding = false;
@@ -2449,6 +3407,49 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        _ => todo!()
                }
        }
+
+       /// If we receive an error message when attempting to open a channel, it may only be a rejection
+       /// of the channel type we tried, not of our ability to open any channel at all. We can see if a
+       /// downgrade of channel features would be possible so that we can still open the channel.
+       pub(crate) fn maybe_downgrade_channel_features<F: Deref>(
+               &mut self, fee_estimator: &LowerBoundedFeeEstimator<F>
+       ) -> Result<(), ()>
+       where
+               F::Target: FeeEstimator
+       {
+               if !self.is_outbound() ||
+                       !matches!(
+                               self.channel_state, ChannelState::NegotiatingFunding(flags)
+                               if flags == NegotiatingFundingFlags::OUR_INIT_SENT
+                       )
+               {
+                       return Err(());
+               }
+               if self.channel_type == ChannelTypeFeatures::only_static_remote_key() {
+                       // We've exhausted our options
+                       return Err(());
+               }
+               // We support opening a few different types of channels. Try removing our additional
+               // features one by one until we've either arrived at our default or the counterparty has
+               // accepted one.
+               //
+               // Due to the order below, we may not negotiate `option_anchors_zero_fee_htlc_tx` if the
+               // counterparty doesn't support `option_scid_privacy`. Since `get_initial_channel_type`
+               // checks whether the counterparty supports every feature, this would only happen if the
+               // counterparty is advertising the feature, but rejecting channels proposing the feature for
+               // whatever reason.
+               if self.channel_type.supports_anchors_zero_fee_htlc_tx() {
+                       self.channel_type.clear_anchors_zero_fee_htlc_tx();
+                       self.feerate_per_kw = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
+                       assert!(!self.channel_transaction_parameters.channel_type_features.supports_anchors_nonzero_fee_htlc_tx());
+               } else if self.channel_type.supports_scid_privacy() {
+                       self.channel_type.clear_scid_privacy();
+               } else {
+                       self.channel_type = ChannelTypeFeatures::only_static_remote_key();
+               }
+               self.channel_transaction_parameters.channel_type_features = self.channel_type.clone();
+               Ok(())
+       }
 }
 
 // Internal utility functions for channels
@@ -2493,6 +3494,20 @@ pub(crate) fn get_legacy_default_holder_selected_channel_reserve_satoshis(channe
        cmp::min(channel_value_satoshis, cmp::max(q, 1000))
 }
 
+/// Returns a minimum channel reserve value each party needs to maintain, fixed in the spec to a
+/// default of 1% of the total channel value.
+///
+/// Guaranteed to return a value no larger than channel_value_satoshis
+///
+/// This is used both for outbound and inbound channels and has lower bound
+/// of `dust_limit_satoshis`.
+#[cfg(any(dual_funding, splicing))]
+fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satoshis: u64) -> u64 {
+       // Fixed at 1% of channel value by spec.
+       let (q, _) = channel_value_satoshis.overflowing_div(100);
+       cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
+}
+
 // Get the fee cost in SATS of a commitment tx with a given number of HTLC outputs.
 // Note that num_htlcs should not include dust HTLCs.
 #[inline]
@@ -2508,10 +3523,26 @@ pub(crate) fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, channel_
        (commitment_tx_base_weight(channel_type_features) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000
 }
 
+/// Context for dual-funded channels.
+#[cfg(any(dual_funding, splicing))]
+pub(super) struct DualFundingChannelContext {
+       /// The amount in satoshis we will be contributing to the channel.
+       pub our_funding_satoshis: u64,
+       /// The amount in satoshis our counterparty will be contributing to the channel.
+       pub their_funding_satoshis: u64,
+       /// The funding transaction locktime suggested by the initiator. If set by us, it is always set
+       /// to the current block height to align incentives against fee-sniping.
+       pub funding_tx_locktime: u32,
+       /// The feerate set by the initiator to be used for the funding transaction.
+       pub funding_feerate_sat_per_1000_weight: u32,
+}
+
 // Holder designates channel data owned for the benefit of the user client.
 // Counterparty designates channel data owned by the another channel participant entity.
 pub(super) struct Channel<SP: Deref> where SP::Target: SignerProvider {
        pub context: ChannelContext<SP>,
+       #[cfg(any(dual_funding, splicing))]
+       pub dual_funding_channel_context: Option<DualFundingChannelContext>,
 }
 
 #[cfg(any(test, fuzzing))]
@@ -2695,7 +3726,7 @@ impl<SP: Deref> Channel<SP> where
        where L::Target: Logger {
                // Assert that we'll add the HTLC claim to the holding cell in `get_update_fulfill_htlc`
                // (see equivalent if condition there).
-               assert!(self.context.channel_state.should_force_holding_cell());
+               assert!(!self.context.channel_state.can_generate_new_commitment());
                let mon_update_id = self.context.latest_monitor_update_id; // Forget the ChannelMonitor update
                let fulfill_resp = self.get_update_fulfill_htlc(htlc_id_arg, payment_preimage_arg, logger);
                self.context.latest_monitor_update_id = mon_update_id;
@@ -2759,12 +3790,14 @@ impl<SP: Deref> Channel<SP> where
                self.context.latest_monitor_update_id += 1;
                let monitor_update = ChannelMonitorUpdate {
                        update_id: self.context.latest_monitor_update_id,
+                       counterparty_node_id: Some(self.context.counterparty_node_id),
                        updates: vec![ChannelMonitorUpdateStep::PaymentPreimage {
                                payment_preimage: payment_preimage_arg.clone(),
                        }],
+                       channel_id: Some(self.context.channel_id()),
                };
 
-               if self.context.channel_state.should_force_holding_cell() {
+               if !self.context.channel_state.can_generate_new_commitment() {
                        // Note that this condition is the same as the assertion in
                        // `claim_htlc_while_disconnected_dropping_mon_update` and must match exactly -
                        // `claim_htlc_while_disconnected_dropping_mon_update` would not work correctly if we
@@ -2938,7 +3971,7 @@ impl<SP: Deref> Channel<SP> where
                        return Ok(None);
                }
 
-               if self.context.channel_state.should_force_holding_cell() {
+               if !self.context.channel_state.can_generate_new_commitment() {
                        debug_assert!(force_holding_cell, "!force_holding_cell is only called when emptying the holding cell, so we shouldn't end up back in it!");
                        force_holding_cell = true;
                }
@@ -2990,6 +4023,20 @@ impl<SP: Deref> Channel<SP> where
                self.context.channel_state.clear_waiting_for_batch();
        }
 
+       /// Unsets the existing funding information.
+       ///
+       /// This must only be used if the channel has not yet completed funding and has not been used.
+       ///
+       /// Further, the channel must be immediately shut down after this with a call to
+       /// [`ChannelContext::force_shutdown`].
+       pub fn unset_funding_info(&mut self, temporary_channel_id: ChannelId) {
+               debug_assert!(matches!(
+                       self.context.channel_state, ChannelState::AwaitingChannelReady(_)
+               ));
+               self.context.channel_transaction_parameters.funding_outpoint = None;
+               self.context.channel_id = temporary_channel_id;
+       }
+
        /// Handles a channel_ready message from our peer. If we've already sent our channel_ready
        /// and the channel is now usable (and public), this may generate an announcement_signatures to
        /// reply with.
@@ -3020,12 +4067,12 @@ impl<SP: Deref> Channel<SP> where
                let mut check_reconnection = false;
                match &self.context.channel_state {
                        ChannelState::AwaitingChannelReady(flags) => {
-                               let flags = *flags & !FundedStateFlags::ALL;
+                               let flags = flags.clone().clear(FundedStateFlags::ALL.into());
                                debug_assert!(!flags.is_set(AwaitingChannelReadyFlags::OUR_CHANNEL_READY) || !flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH));
-                               if flags & !AwaitingChannelReadyFlags::WAITING_FOR_BATCH == AwaitingChannelReadyFlags::THEIR_CHANNEL_READY {
+                               if flags.clone().clear(AwaitingChannelReadyFlags::WAITING_FOR_BATCH) == AwaitingChannelReadyFlags::THEIR_CHANNEL_READY {
                                        // If we reconnected before sending our `channel_ready` they may still resend theirs.
                                        check_reconnection = true;
-                               } else if (flags & !AwaitingChannelReadyFlags::WAITING_FOR_BATCH).is_empty() {
+                               } else if flags.clone().clear(AwaitingChannelReadyFlags::WAITING_FOR_BATCH).is_empty() {
                                        self.context.channel_state.set_their_channel_ready();
                                } else if flags == AwaitingChannelReadyFlags::OUR_CHANNEL_READY {
                                        self.context.channel_state = ChannelState::ChannelReady(self.context.channel_state.with_funded_state_flags_mask().into());
@@ -3070,23 +4117,15 @@ impl<SP: Deref> Channel<SP> where
 
                log_info!(logger, "Received channel_ready from peer for channel {}", &self.context.channel_id());
 
-               Ok(self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height(), logger))
+               Ok(self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height, logger))
        }
 
-       pub fn update_add_htlc<F, FE: Deref, L: Deref>(
-               &mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus,
-               create_pending_htlc_status: F, fee_estimator: &LowerBoundedFeeEstimator<FE>, logger: &L
-       ) -> Result<(), ChannelError>
-       where F: for<'a> Fn(&'a Self, PendingHTLCStatus, u16) -> PendingHTLCStatus,
-               FE::Target: FeeEstimator, L::Target: Logger,
-       {
+       pub fn update_add_htlc(
+               &mut self, msg: &msgs::UpdateAddHTLC, pending_forward_status: PendingHTLCStatus,
+       ) -> Result<(), ChannelError> {
                if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
                }
-               // We can't accept HTLCs sent after we've sent a shutdown.
-               if self.context.channel_state.is_local_shutdown_sent() {
-                       pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x4000|8);
-               }
                // If the remote has sent a shutdown prior to adding this HTLC, then they are in violation of the spec.
                if self.context.channel_state.is_remote_shutdown_sent() {
                        return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
@@ -3105,7 +4144,6 @@ impl<SP: Deref> Channel<SP> where
                }
 
                let inbound_stats = self.context.get_inbound_pending_htlc_stats(None);
-               let outbound_stats = self.context.get_outbound_pending_htlc_stats(None);
                if inbound_stats.pending_htlcs + 1 > self.context.holder_max_accepted_htlcs as u32 {
                        return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", self.context.holder_max_accepted_htlcs)));
                }
@@ -3134,34 +4172,6 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
-               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(fee_estimator);
-               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                       (0, 0)
-               } else {
-                       let dust_buffer_feerate = self.context.get_dust_buffer_feerate(None) as u64;
-                       (dust_buffer_feerate * htlc_timeout_tx_weight(self.context.get_channel_type()) / 1000,
-                               dust_buffer_feerate * htlc_success_tx_weight(self.context.get_channel_type()) / 1000)
-               };
-               let exposure_dust_limit_timeout_sats = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
-               if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
-                       let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
-                       if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
-                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
-                                       on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
-                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
-                       }
-               }
-
-               let exposure_dust_limit_success_sats = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
-               if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
-                       let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
-                       if on_holder_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
-                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
-                                       on_holder_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
-                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
-                       }
-               }
-
                let pending_value_to_self_msat =
                        self.context.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
                let pending_remote_value_msat =
@@ -3195,23 +4205,7 @@ impl<SP: Deref> Channel<SP> where
                } else {
                        0
                };
-               if !self.context.is_outbound() {
-                       // `Some(())` is for the fee spike buffer we keep for the remote. This deviates from
-                       // the spec because the fee spike buffer requirement doesn't exist on the receiver's
-                       // side, only on the sender's. Note that with anchor outputs we are no longer as
-                       // sensitive to fee spikes, so we need to account for them.
-                       let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
-                       let mut remote_fee_cost_incl_stuck_buffer_msat = self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
-                       if !self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                               remote_fee_cost_incl_stuck_buffer_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE;
-                       }
-                       if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(self.context.holder_selected_channel_reserve_satoshis * 1000).saturating_sub(anchor_outputs_value_msat) < remote_fee_cost_incl_stuck_buffer_msat {
-                               // Note that if the pending_forward_status is not updated here, then it's because we're already failing
-                               // the HTLC, i.e. its status is already set to failing.
-                               log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", &self.context.channel_id());
-                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
-                       }
-               } else {
+               if self.context.is_outbound() {
                        // Check that they won't violate our local required channel reserve by adding this HTLC.
                        let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
                        let local_commit_tx_fee_msat = self.context.next_local_commit_tx_fee_msat(htlc_candidate, None);
@@ -3239,7 +4233,9 @@ impl<SP: Deref> Channel<SP> where
                        amount_msat: msg.amount_msat,
                        payment_hash: msg.payment_hash,
                        cltv_expiry: msg.cltv_expiry,
-                       state: InboundHTLCState::RemoteAnnounced(pending_forward_status),
+                       state: InboundHTLCState::RemoteAnnounced(InboundHTLCResolution::Resolved {
+                               pending_htlc_status: pending_forward_status
+                       }),
                });
                Ok(())
        }
@@ -3275,7 +4271,7 @@ impl<SP: Deref> Channel<SP> where
                Err(ChannelError::Close("Remote tried to fulfill/fail an HTLC we couldn't find".to_owned()))
        }
 
-       pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<(HTLCSource, u64), ChannelError> {
+       pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<(HTLCSource, u64, Option<u64>), ChannelError> {
                if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got fulfill HTLC message when channel was not in an operational state".to_owned()));
                }
@@ -3283,7 +4279,7 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Close("Peer sent update_fulfill_htlc when we needed a channel_reestablish".to_owned()));
                }
 
-               self.mark_outbound_htlc_removed(msg.htlc_id, Some(msg.payment_preimage), None).map(|htlc| (htlc.source.clone(), htlc.amount_msat))
+               self.mark_outbound_htlc_removed(msg.htlc_id, Some(msg.payment_preimage), None).map(|htlc| (htlc.source.clone(), htlc.amount_msat, htlc.skimmed_fee_msat))
        }
 
        pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC, fail_reason: HTLCFailReason) -> Result<(), ChannelError> {
@@ -3445,13 +4441,13 @@ impl<SP: Deref> Channel<SP> where
                }
 
                for htlc in self.context.pending_inbound_htlcs.iter_mut() {
-                       let new_forward = if let &InboundHTLCState::RemoteAnnounced(ref forward_info) = &htlc.state {
-                               Some(forward_info.clone())
+                       let htlc_resolution = if let &InboundHTLCState::RemoteAnnounced(ref resolution) = &htlc.state {
+                               Some(resolution.clone())
                        } else { None };
-                       if let Some(forward_info) = new_forward {
+                       if let Some(htlc_resolution) = htlc_resolution {
                                log_trace!(logger, "Updating HTLC {} to AwaitingRemoteRevokeToAnnounce due to commitment_signed in channel {}.",
                                        &htlc.payment_hash, &self.context.channel_id);
-                               htlc.state = InboundHTLCState::AwaitingRemoteRevokeToAnnounce(forward_info);
+                               htlc.state = InboundHTLCState::AwaitingRemoteRevokeToAnnounce(htlc_resolution);
                                need_commitment = true;
                        }
                }
@@ -3480,12 +4476,14 @@ impl<SP: Deref> Channel<SP> where
                self.context.latest_monitor_update_id += 1;
                let mut monitor_update = ChannelMonitorUpdate {
                        update_id: self.context.latest_monitor_update_id,
+                       counterparty_node_id: Some(self.context.counterparty_node_id),
                        updates: vec![ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo {
                                commitment_tx: holder_commitment_tx,
                                htlc_outputs: htlcs_and_sigs,
                                claimed_htlcs,
                                nondust_htlc_sources,
-                       }]
+                       }],
+                       channel_id: Some(self.context.channel_id()),
                };
 
                self.context.cur_holder_commitment_transaction_number -= 1;
@@ -3540,7 +4538,7 @@ impl<SP: Deref> Channel<SP> where
        ) -> (Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>)
        where F::Target: FeeEstimator, L::Target: Logger
        {
-               if matches!(self.context.channel_state, ChannelState::ChannelReady(_)) && !self.context.channel_state.should_force_holding_cell() {
+               if matches!(self.context.channel_state, ChannelState::ChannelReady(_)) && self.context.channel_state.can_generate_new_commitment() {
                        self.free_holding_cell_htlcs(fee_estimator, logger)
                } else { (None, Vec::new()) }
        }
@@ -3559,7 +4557,9 @@ impl<SP: Deref> Channel<SP> where
 
                        let mut monitor_update = ChannelMonitorUpdate {
                                update_id: self.context.latest_monitor_update_id + 1, // We don't increment this yet!
+                               counterparty_node_id: Some(self.context.counterparty_node_id),
                                updates: Vec::new(),
+                               channel_id: Some(self.context.channel_id()),
                        };
 
                        let mut htlc_updates = Vec::new();
@@ -3733,10 +4733,12 @@ impl<SP: Deref> Channel<SP> where
                self.context.latest_monitor_update_id += 1;
                let mut monitor_update = ChannelMonitorUpdate {
                        update_id: self.context.latest_monitor_update_id,
+                       counterparty_node_id: Some(self.context.counterparty_node_id),
                        updates: vec![ChannelMonitorUpdateStep::CommitmentSecret {
                                idx: self.context.cur_counterparty_commitment_transaction_number + 1,
                                secret: msg.per_commitment_secret,
                        }],
+                       channel_id: Some(self.context.channel_id()),
                };
 
                // Update state now that we've passed all the can-fail calls...
@@ -3755,6 +4757,7 @@ impl<SP: Deref> Channel<SP> where
 
                log_trace!(logger, "Updating HTLCs on receipt of RAA in channel {}...", &self.context.channel_id());
                let mut to_forward_infos = Vec::new();
+               let mut pending_update_adds = Vec::new();
                let mut revoked_htlcs = Vec::new();
                let mut finalized_claimed_htlcs = Vec::new();
                let mut update_fail_htlcs = Vec::new();
@@ -3802,29 +4805,37 @@ impl<SP: Deref> Channel<SP> where
                                        let mut state = InboundHTLCState::Committed;
                                        mem::swap(&mut state, &mut htlc.state);
 
-                                       if let InboundHTLCState::AwaitingRemoteRevokeToAnnounce(forward_info) = state {
+                                       if let InboundHTLCState::AwaitingRemoteRevokeToAnnounce(resolution) = state {
                                                log_trace!(logger, " ...promoting inbound AwaitingRemoteRevokeToAnnounce {} to AwaitingAnnouncedRemoteRevoke", &htlc.payment_hash);
-                                               htlc.state = InboundHTLCState::AwaitingAnnouncedRemoteRevoke(forward_info);
+                                               htlc.state = InboundHTLCState::AwaitingAnnouncedRemoteRevoke(resolution);
                                                require_commitment = true;
-                                       } else if let InboundHTLCState::AwaitingAnnouncedRemoteRevoke(forward_info) = state {
-                                               match forward_info {
-                                                       PendingHTLCStatus::Fail(fail_msg) => {
-                                                               log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to LocalRemoved due to PendingHTLCStatus indicating failure", &htlc.payment_hash);
-                                                               require_commitment = true;
-                                                               match fail_msg {
-                                                                       HTLCFailureMsg::Relay(msg) => {
-                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(msg.reason.clone()));
-                                                                               update_fail_htlcs.push(msg)
-                                                                       },
-                                                                       HTLCFailureMsg::Malformed(msg) => {
-                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailMalformed((msg.sha256_of_onion, msg.failure_code)));
-                                                                               update_fail_malformed_htlcs.push(msg)
+                                       } else if let InboundHTLCState::AwaitingAnnouncedRemoteRevoke(resolution) = state {
+                                               match resolution {
+                                                       InboundHTLCResolution::Resolved { pending_htlc_status } =>
+                                                               match pending_htlc_status {
+                                                                       PendingHTLCStatus::Fail(fail_msg) => {
+                                                                               log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to LocalRemoved due to PendingHTLCStatus indicating failure", &htlc.payment_hash);
+                                                                               require_commitment = true;
+                                                                               match fail_msg {
+                                                                                       HTLCFailureMsg::Relay(msg) => {
+                                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(msg.reason.clone()));
+                                                                                               update_fail_htlcs.push(msg)
+                                                                                       },
+                                                                                       HTLCFailureMsg::Malformed(msg) => {
+                                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailMalformed((msg.sha256_of_onion, msg.failure_code)));
+                                                                                               update_fail_malformed_htlcs.push(msg)
+                                                                                       },
+                                                                               }
                                                                        },
+                                                                       PendingHTLCStatus::Forward(forward_info) => {
+                                                                               log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to Committed, attempting to forward", &htlc.payment_hash);
+                                                                               to_forward_infos.push((forward_info, htlc.htlc_id));
+                                                                               htlc.state = InboundHTLCState::Committed;
+                                                                       }
                                                                }
-                                                       },
-                                                       PendingHTLCStatus::Forward(forward_info) => {
+                                                       InboundHTLCResolution::Pending { update_add_htlc } => {
                                                                log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to Committed", &htlc.payment_hash);
-                                                               to_forward_infos.push((forward_info, htlc.htlc_id));
+                                                               pending_update_adds.push(update_add_htlc);
                                                                htlc.state = InboundHTLCState::Committed;
                                                        }
                                                }
@@ -3885,6 +4896,8 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
+               self.context.monitor_pending_update_adds.append(&mut pending_update_adds);
+
                if self.context.channel_state.is_monitor_update_in_progress() {
                        // We can't actually generate a new commitment transaction (incl by freeing holding
                        // cells) while we can't update the monitor, so we just return what we have.
@@ -4148,8 +5161,8 @@ impl<SP: Deref> Channel<SP> where
                // first received the funding_signed.
                let mut funding_broadcastable =
                        if self.context.is_outbound() &&
-                               matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(flags) if !flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH)) ||
-                               matches!(self.context.channel_state, ChannelState::ChannelReady(_))
+                               (matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(flags) if !flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH)) ||
+                               matches!(self.context.channel_state, ChannelState::ChannelReady(_)))
                        {
                                self.context.funding_transaction.take()
                        } else { None };
@@ -4185,13 +5198,16 @@ impl<SP: Deref> Channel<SP> where
                mem::swap(&mut failed_htlcs, &mut self.context.monitor_pending_failures);
                let mut finalized_claimed_htlcs = Vec::new();
                mem::swap(&mut finalized_claimed_htlcs, &mut self.context.monitor_pending_finalized_fulfills);
+               let mut pending_update_adds = Vec::new();
+               mem::swap(&mut pending_update_adds, &mut self.context.monitor_pending_update_adds);
 
                if self.context.channel_state.is_peer_disconnected() {
                        self.context.monitor_pending_revoke_and_ack = false;
                        self.context.monitor_pending_commitment_signed = false;
                        return MonitorRestoreUpdates {
                                raa: None, commitment_update: None, order: RAACommitmentOrder::RevokeAndACKFirst,
-                               accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, funding_broadcastable, channel_ready, announcement_sigs
+                               accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, pending_update_adds,
+                               funding_broadcastable, channel_ready, announcement_sigs
                        };
                }
 
@@ -4213,7 +5229,8 @@ impl<SP: Deref> Channel<SP> where
                        if commitment_update.is_some() { "a" } else { "no" }, if raa.is_some() { "an" } else { "no" },
                        match order { RAACommitmentOrder::CommitmentFirst => "commitment", RAACommitmentOrder::RevokeAndACKFirst => "RAA"});
                MonitorRestoreUpdates {
-                       raa, commitment_update, order, accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, funding_broadcastable, channel_ready, announcement_sigs
+                       raa, commitment_update, order, accepted_htlcs, failed_htlcs, finalized_claimed_htlcs,
+                       pending_update_adds, funding_broadcastable, channel_ready, announcement_sigs
                }
        }
 
@@ -4251,7 +5268,7 @@ impl<SP: Deref> Channel<SP> where
 
        /// Indicates that the signer may have some signatures for us, so we should retry if we're
        /// blocked.
-       #[allow(unused)]
+       #[cfg(async_signing)]
        pub fn signer_maybe_unblocked<L: Deref>(&mut self, logger: &L) -> SignerResumeUpdates where L::Target: Logger {
                let commitment_update = if self.context.signer_pending_commitment_update {
                        self.get_last_commitment_update_for_send(logger).ok()
@@ -4355,11 +5372,16 @@ impl<SP: Deref> Channel<SP> where
                        }
                        update
                } else {
-                       if !self.context.signer_pending_commitment_update {
-                               log_trace!(logger, "Commitment update awaiting signer: setting signer_pending_commitment_update");
-                               self.context.signer_pending_commitment_update = true;
+                       #[cfg(not(async_signing))] {
+                               panic!("Failed to get signature for new commitment state");
+                       }
+                       #[cfg(async_signing)] {
+                               if !self.context.signer_pending_commitment_update {
+                                       log_trace!(logger, "Commitment update awaiting signer: setting signer_pending_commitment_update");
+                                       self.context.signer_pending_commitment_update = true;
+                               }
+                               return Err(());
                        }
-                       return Err(());
                };
                Ok(msgs::CommitmentUpdate {
                        update_add_htlcs, update_fulfill_htlcs, update_fail_htlcs, update_fail_malformed_htlcs, update_fee,
@@ -4448,7 +5470,7 @@ impl<SP: Deref> Channel<SP> where
 
                let shutdown_msg = self.get_outbound_shutdown();
 
-               let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height(), logger);
+               let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height, logger);
 
                if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(_)) {
                        // If we're waiting on a monitor update, we shouldn't re-send any channel_ready's.
@@ -4785,9 +5807,11 @@ impl<SP: Deref> Channel<SP> where
                        self.context.latest_monitor_update_id += 1;
                        let monitor_update = ChannelMonitorUpdate {
                                update_id: self.context.latest_monitor_update_id,
+                               counterparty_node_id: Some(self.context.counterparty_node_id),
                                updates: vec![ChannelMonitorUpdateStep::ShutdownScript {
                                        scriptpubkey: self.get_closing_scriptpubkey(),
                                }],
+                               channel_id: Some(self.context.channel_id()),
                        };
                        self.monitor_updating_paused(false, false, false, Vec::new(), Vec::new(), Vec::new());
                        self.push_ret_blockable_mon_update(monitor_update)
@@ -4894,15 +5918,26 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
+               let closure_reason = if self.initiated_shutdown() {
+                       ClosureReason::LocallyInitiatedCooperativeClosure
+               } else {
+                       ClosureReason::CounterpartyInitiatedCooperativeClosure
+               };
+
                assert!(self.context.shutdown_scriptpubkey.is_some());
                if let Some((last_fee, sig)) = self.context.last_sent_closing_fee {
                        if last_fee == msg.fee_satoshis {
                                let shutdown_result = ShutdownResult {
+                                       closure_reason,
                                        monitor_update: None,
                                        dropped_outbound_htlcs: Vec::new(),
                                        unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
                                        channel_id: self.context.channel_id,
+                                       user_channel_id: self.context.user_id,
+                                       channel_capacity_satoshis: self.context.channel_value_satoshis,
                                        counterparty_node_id: self.context.counterparty_node_id,
+                                       unbroadcasted_funding_tx: self.context.unbroadcasted_funding(),
+                                       channel_funding_txo: self.context.get_funding_txo(),
                                };
                                let tx = self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
                                self.context.channel_state = ChannelState::ShutdownComplete;
@@ -4928,11 +5963,16 @@ impl<SP: Deref> Channel<SP> where
                                                        .map_err(|_| ChannelError::Close("External signer refused to sign closing transaction".to_owned()))?;
                                                let (signed_tx, shutdown_result) = if $new_fee == msg.fee_satoshis {
                                                        let shutdown_result = ShutdownResult {
+                                                               closure_reason,
                                                                monitor_update: None,
                                                                dropped_outbound_htlcs: Vec::new(),
                                                                unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
                                                                channel_id: self.context.channel_id,
+                                                               user_channel_id: self.context.user_id,
+                                                               channel_capacity_satoshis: self.context.channel_value_satoshis,
                                                                counterparty_node_id: self.context.counterparty_node_id,
+                                                               unbroadcasted_funding_tx: self.context.unbroadcasted_funding(),
+                                                               channel_funding_txo: self.context.get_funding_txo(),
                                                        };
                                                        self.context.channel_state = ChannelState::ShutdownComplete;
                                                        self.context.update_time_counter += 1;
@@ -5054,6 +6094,86 @@ impl<SP: Deref> Channel<SP> where
                        })
        }
 
+       pub fn can_accept_incoming_htlc<F: Deref, L: Deref>(
+               &self, msg: &msgs::UpdateAddHTLC, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L
+       ) -> Result<(), (&'static str, u16)>
+       where
+               F::Target: FeeEstimator,
+               L::Target: Logger
+       {
+               if self.context.channel_state.is_local_shutdown_sent() {
+                       return Err(("Shutdown was already sent", 0x4000|8))
+               }
+
+               let inbound_stats = self.context.get_inbound_pending_htlc_stats(None);
+               let outbound_stats = self.context.get_outbound_pending_htlc_stats(None);
+               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(fee_estimator);
+               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                       (0, 0)
+               } else {
+                       let dust_buffer_feerate = self.context.get_dust_buffer_feerate(None) as u64;
+                       (dust_buffer_feerate * htlc_timeout_tx_weight(self.context.get_channel_type()) / 1000,
+                               dust_buffer_feerate * htlc_success_tx_weight(self.context.get_channel_type()) / 1000)
+               };
+               let exposure_dust_limit_timeout_sats = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
+                       let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+                                       on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
+                               return Err(("Exceeded our dust exposure limit on counterparty commitment tx", 0x1000|7))
+                       }
+               }
+
+               let exposure_dust_limit_success_sats = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
+                       let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_holder_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
+                                       on_holder_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
+                               return Err(("Exceeded our dust exposure limit on holder commitment tx", 0x1000|7))
+                       }
+               }
+
+               let anchor_outputs_value_msat = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                       ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000
+               } else {
+                       0
+               };
+
+               let mut removed_outbound_total_msat = 0;
+               for ref htlc in self.context.pending_outbound_htlcs.iter() {
+                       if let OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_)) = htlc.state {
+                               removed_outbound_total_msat += htlc.amount_msat;
+                       } else if let OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_)) = htlc.state {
+                               removed_outbound_total_msat += htlc.amount_msat;
+                       }
+               }
+
+               let pending_value_to_self_msat =
+                       self.context.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
+               let pending_remote_value_msat =
+                       self.context.channel_value_satoshis * 1000 - pending_value_to_self_msat;
+
+               if !self.context.is_outbound() {
+                       // `Some(())` is for the fee spike buffer we keep for the remote. This deviates from
+                       // the spec because the fee spike buffer requirement doesn't exist on the receiver's
+                       // side, only on the sender's. Note that with anchor outputs we are no longer as
+                       // sensitive to fee spikes, so we need to account for them.
+                       let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
+                       let mut remote_fee_cost_incl_stuck_buffer_msat = self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
+                       if !self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                               remote_fee_cost_incl_stuck_buffer_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE;
+                       }
+                       if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(self.context.holder_selected_channel_reserve_satoshis * 1000).saturating_sub(anchor_outputs_value_msat) < remote_fee_cost_incl_stuck_buffer_msat {
+                               log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", &self.context.channel_id());
+                               return Err(("Fee spike buffer violation", 0x1000|7));
+                       }
+               }
+
+               Ok(())
+       }
+
        pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
                self.context.cur_holder_commitment_transaction_number + 1
        }
@@ -5143,7 +6263,7 @@ impl<SP: Deref> Channel<SP> where
                if !self.is_awaiting_monitor_update() { return false; }
                if matches!(
                        self.context.channel_state, ChannelState::AwaitingChannelReady(flags)
-                       if (flags & !(AwaitingChannelReadyFlags::THEIR_CHANNEL_READY | FundedStateFlags::PEER_DISCONNECTED | FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS | AwaitingChannelReadyFlags::WAITING_FOR_BATCH)).is_empty()
+                       if flags.clone().clear(AwaitingChannelReadyFlags::THEIR_CHANNEL_READY | FundedStateFlags::PEER_DISCONNECTED | FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS | AwaitingChannelReadyFlags::WAITING_FOR_BATCH).is_empty()
                ) {
                        // If we're not a 0conf channel, we'll be waiting on a monitor update with only
                        // AwaitingChannelReady set, though our peer could have sent their channel_ready.
@@ -5188,6 +6308,11 @@ impl<SP: Deref> Channel<SP> where
                self.context.channel_state.is_local_shutdown_sent()
        }
 
+       /// Returns true if we initiated to shut down the channel.
+       pub fn initiated_shutdown(&self) -> bool {
+               self.context.local_initiated_shutdown.is_some()
+       }
+
        /// Returns true if this channel is fully shut down. True here implies that no further actions
        /// may/will be taken on this channel, and thus this object should be freed. Any future changes
        /// will be handled appropriately by the chain monitor.
@@ -5229,14 +6354,14 @@ impl<SP: Deref> Channel<SP> where
 
                // Note that we don't include ChannelState::WaitingForBatch as we don't want to send
                // channel_ready until the entire batch is ready.
-               let need_commitment_update = if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if (f & !FundedStateFlags::ALL).is_empty()) {
+               let need_commitment_update = if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f.clone().clear(FundedStateFlags::ALL.into()).is_empty()) {
                        self.context.channel_state.set_our_channel_ready();
                        true
-               } else if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f & !FundedStateFlags::ALL == AwaitingChannelReadyFlags::THEIR_CHANNEL_READY) {
+               } else if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f.clone().clear(FundedStateFlags::ALL.into()) == AwaitingChannelReadyFlags::THEIR_CHANNEL_READY) {
                        self.context.channel_state = ChannelState::ChannelReady(self.context.channel_state.with_funded_state_flags_mask().into());
                        self.context.update_time_counter += 1;
                        true
-               } else if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f & !FundedStateFlags::ALL == AwaitingChannelReadyFlags::OUR_CHANNEL_READY) {
+               } else if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f.clone().clear(FundedStateFlags::ALL.into()) == AwaitingChannelReadyFlags::OUR_CHANNEL_READY) {
                        // We got a reorg but not enough to trigger a force close, just ignore.
                        false
                } else {
@@ -5811,7 +6936,7 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected from channel counterparty".to_owned()));
                }
 
-               let need_holding_cell = self.context.channel_state.should_force_holding_cell();
+               let need_holding_cell = !self.context.channel_state.can_generate_new_commitment();
                log_debug!(logger, "Pushing new outbound HTLC with hash {} for {} msat {}",
                        payment_hash, amount_msat,
                        if force_holding_cell { "into holding cell" }
@@ -5908,6 +7033,7 @@ impl<SP: Deref> Channel<SP> where
                self.context.latest_monitor_update_id += 1;
                let monitor_update = ChannelMonitorUpdate {
                        update_id: self.context.latest_monitor_update_id,
+                       counterparty_node_id: Some(self.context.counterparty_node_id),
                        updates: vec![ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo {
                                commitment_txid: counterparty_commitment_txid,
                                htlc_outputs: htlcs.clone(),
@@ -5916,7 +7042,8 @@ impl<SP: Deref> Channel<SP> where
                                feerate_per_kw: Some(counterparty_commitment_tx.feerate_per_kw()),
                                to_broadcaster_value_sat: Some(counterparty_commitment_tx.to_broadcaster_value_sat()),
                                to_countersignatory_value_sat: Some(counterparty_commitment_tx.to_countersignatory_value_sat()),
-                       }]
+                       }],
+                       channel_id: Some(self.context.channel_id()),
                };
                self.context.channel_state.set_awaiting_remote_revoke();
                monitor_update
@@ -6100,15 +7227,18 @@ impl<SP: Deref> Channel<SP> where
                // From here on out, we may not fail!
                self.context.target_closing_feerate_sats_per_kw = target_feerate_sats_per_kw;
                self.context.channel_state.set_local_shutdown_sent();
+               self.context.local_initiated_shutdown = Some(());
                self.context.update_time_counter += 1;
 
                let monitor_update = if update_shutdown_script {
                        self.context.latest_monitor_update_id += 1;
                        let monitor_update = ChannelMonitorUpdate {
                                update_id: self.context.latest_monitor_update_id,
+                               counterparty_node_id: Some(self.context.counterparty_node_id),
                                updates: vec![ChannelMonitorUpdateStep::ShutdownScript {
                                        scriptpubkey: self.get_closing_scriptpubkey(),
                                }],
+                               channel_id: Some(self.context.channel_id()),
                        };
                        self.monitor_updating_paused(false, false, false, Vec::new(), Vec::new(), Vec::new());
                        self.push_ret_blockable_mon_update(monitor_update)
@@ -6166,222 +7296,61 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
        where ES::Target: EntropySource,
              F::Target: FeeEstimator
        {
-               let holder_selected_contest_delay = config.channel_handshake_config.our_to_self_delay;
-               let channel_keys_id = signer_provider.generate_channel_keys_id(false, channel_value_satoshis, user_id);
-               let holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
-               let pubkeys = holder_signer.pubkeys().clone();
-
-               if !their_features.supports_wumbo() && channel_value_satoshis > MAX_FUNDING_SATOSHIS_NO_WUMBO {
-                       return Err(APIError::APIMisuseError{err: format!("funding_value must not exceed {}, it was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, channel_value_satoshis)});
-               }
-               if channel_value_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
-                       return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than the total bitcoin supply, it was {}", channel_value_satoshis)});
-               }
-               let channel_value_msat = channel_value_satoshis * 1000;
-               if push_msat > channel_value_msat {
-                       return Err(APIError::APIMisuseError { err: format!("Push value ({}) was larger than channel_value ({})", push_msat, channel_value_msat) });
-               }
-               if holder_selected_contest_delay < BREAKDOWN_TIMEOUT {
-                       return Err(APIError::APIMisuseError {err: format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks", holder_selected_contest_delay)});
-               }
                let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(channel_value_satoshis, config);
                if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
                        // Protocol level safety check in place, although it should never happen because
                        // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
-                       return Err(APIError::APIMisuseError { err: format!("Holder selected channel  reserve below implemention limit dust_limit_satoshis {}", holder_selected_channel_reserve_satoshis) });
+                       return Err(APIError::APIMisuseError { err: format!("Holder selected channel reserve below \
+                               implemention limit dust_limit_satoshis {}", holder_selected_channel_reserve_satoshis) });
                }
 
-               let channel_type = Self::get_initial_channel_type(&config, their_features);
-               debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config)));
+               let channel_keys_id = signer_provider.generate_channel_keys_id(false, channel_value_satoshis, user_id);
+               let holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
+               let pubkeys = holder_signer.pubkeys().clone();
 
-               let (commitment_conf_target, anchor_outputs_value_msat)  = if channel_type.supports_anchors_zero_fee_htlc_tx() {
-                       (ConfirmationTarget::AnchorChannelFee, ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000)
-               } else {
-                       (ConfirmationTarget::NonAnchorChannelFee, 0)
+               let chan = Self {
+                       context: ChannelContext::new_for_outbound_channel(
+                               fee_estimator,
+                               entropy_source,
+                               signer_provider,
+                               counterparty_node_id,
+                               their_features,
+                               channel_value_satoshis,
+                               push_msat,
+                               user_id,
+                               config,
+                               current_chain_height,
+                               outbound_scid_alias,
+                               temporary_channel_id,
+                               holder_selected_channel_reserve_satoshis,
+                               channel_keys_id,
+                               holder_signer,
+                               pubkeys,
+                       )?,
+                       unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 }
                };
-               let commitment_feerate = fee_estimator.bounded_sat_per_1000_weight(commitment_conf_target);
-
-               let value_to_self_msat = channel_value_satoshis * 1000 - push_msat;
-               let commitment_tx_fee = commit_tx_fee_msat(commitment_feerate, MIN_AFFORDABLE_HTLC_COUNT, &channel_type);
-               if value_to_self_msat.saturating_sub(anchor_outputs_value_msat) < commitment_tx_fee {
-                       return Err(APIError::APIMisuseError{ err: format!("Funding amount ({}) can't even pay fee for initial commitment transaction fee of {}.", value_to_self_msat / 1000, commitment_tx_fee / 1000) });
-               }
-
-               let mut secp_ctx = Secp256k1::new();
-               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
-
-               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
-                       match signer_provider.get_shutdown_scriptpubkey() {
-                               Ok(scriptpubkey) => Some(scriptpubkey),
-                               Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get shutdown scriptpubkey".to_owned()}),
-                       }
-               } else { None };
-
-               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
-                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
-                               return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
-                       }
-               }
+               Ok(chan)
+       }
 
-               let destination_script = match signer_provider.get_destination_script(channel_keys_id) {
-                       Ok(script) => script,
-                       Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get destination script".to_owned()}),
+       /// Only allowed after [`ChannelContext::channel_transaction_parameters`] is set.
+       fn get_funding_created_msg<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
+               let signature = match &self.context.holder_signer {
+                       // TODO (taproot|arik): move match into calling method for Taproot
+                       ChannelSignerType::Ecdsa(ecdsa) => {
+                               ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.context.secp_ctx)
+                                       .map(|(sig, _)| sig).ok()?
+                       },
+                       // TODO (taproot|arik)
+                       #[cfg(taproot)]
+                       _ => todo!()
                };
 
-               let temporary_channel_id = temporary_channel_id.unwrap_or_else(|| ChannelId::temporary_from_entropy_source(entropy_source));
-
-               Ok(Self {
-                       context: ChannelContext {
-                               user_id,
-
-                               config: LegacyChannelConfig {
-                                       options: config.channel_config.clone(),
-                                       announced_channel: config.channel_handshake_config.announced_channel,
-                                       commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
-                               },
-
-                               prev_config: None,
-
-                               inbound_handshake_limits_override: Some(config.channel_handshake_limits.clone()),
-
-                               channel_id: temporary_channel_id,
-                               temporary_channel_id: Some(temporary_channel_id),
-                               channel_state: ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT),
-                               announcement_sigs_state: AnnouncementSigsState::NotSent,
-                               secp_ctx,
-                               channel_value_satoshis,
-
-                               latest_monitor_update_id: 0,
-
-                               holder_signer: ChannelSignerType::Ecdsa(holder_signer),
-                               shutdown_scriptpubkey,
-                               destination_script,
-
-                               cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               value_to_self_msat,
-
-                               pending_inbound_htlcs: Vec::new(),
-                               pending_outbound_htlcs: Vec::new(),
-                               holding_cell_htlc_updates: Vec::new(),
-                               pending_update_fee: None,
-                               holding_cell_update_fee: None,
-                               next_holder_htlc_id: 0,
-                               next_counterparty_htlc_id: 0,
-                               update_time_counter: 1,
-
-                               resend_order: RAACommitmentOrder::CommitmentFirst,
-
-                               monitor_pending_channel_ready: false,
-                               monitor_pending_revoke_and_ack: false,
-                               monitor_pending_commitment_signed: false,
-                               monitor_pending_forwards: Vec::new(),
-                               monitor_pending_failures: Vec::new(),
-                               monitor_pending_finalized_fulfills: Vec::new(),
-
-                               signer_pending_commitment_update: false,
-                               signer_pending_funding: false,
-
-                               #[cfg(debug_assertions)]
-                               holder_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
-                               #[cfg(debug_assertions)]
-                               counterparty_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
-
-                               last_sent_closing_fee: None,
-                               pending_counterparty_closing_signed: None,
-                               expecting_peer_commitment_signed: false,
-                               closing_fee_limits: None,
-                               target_closing_feerate_sats_per_kw: None,
-
-                               funding_tx_confirmed_in: None,
-                               funding_tx_confirmation_height: 0,
-                               short_channel_id: None,
-                               channel_creation_height: current_chain_height,
-
-                               feerate_per_kw: commitment_feerate,
-                               counterparty_dust_limit_satoshis: 0,
-                               holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
-                               counterparty_max_htlc_value_in_flight_msat: 0,
-                               holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis, &config.channel_handshake_config),
-                               counterparty_selected_channel_reserve_satoshis: None, // Filled in in accept_channel
-                               holder_selected_channel_reserve_satoshis,
-                               counterparty_htlc_minimum_msat: 0,
-                               holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
-                               counterparty_max_accepted_htlcs: 0,
-                               holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
-                               minimum_depth: None, // Filled in in accept_channel
-
-                               counterparty_forwarding_info: None,
-
-                               channel_transaction_parameters: ChannelTransactionParameters {
-                                       holder_pubkeys: pubkeys,
-                                       holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
-                                       is_outbound_from_holder: true,
-                                       counterparty_parameters: None,
-                                       funding_outpoint: None,
-                                       channel_type_features: channel_type.clone()
-                               },
-                               funding_transaction: None,
-                               is_batch_funding: None,
-
-                               counterparty_cur_commitment_point: None,
-                               counterparty_prev_commitment_point: None,
-                               counterparty_node_id,
-
-                               counterparty_shutdown_scriptpubkey: None,
-
-                               commitment_secrets: CounterpartyCommitmentSecrets::new(),
-
-                               channel_update_status: ChannelUpdateStatus::Enabled,
-                               closing_signed_in_flight: false,
-
-                               announcement_sigs: None,
-
-                               #[cfg(any(test, fuzzing))]
-                               next_local_commitment_tx_fee_info_cached: Mutex::new(None),
-                               #[cfg(any(test, fuzzing))]
-                               next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
-
-                               workaround_lnd_bug_4006: None,
-                               sent_message_awaiting_response: None,
-
-                               latest_inbound_scid_alias: None,
-                               outbound_scid_alias,
-
-                               channel_pending_event_emitted: false,
-                               channel_ready_event_emitted: false,
-
-                               #[cfg(any(test, fuzzing))]
-                               historical_inbound_htlc_fulfills: HashSet::new(),
-
-                               channel_type,
-                               channel_keys_id,
-
-                               blocked_monitor_updates: Vec::new(),
-                       },
-                       unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 }
-               })
-       }
-
-       /// Only allowed after [`ChannelContext::channel_transaction_parameters`] is set.
-       fn get_funding_created_msg<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
-               let counterparty_keys = self.context.build_remote_transaction_keys();
-               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
-               let signature = match &self.context.holder_signer {
-                       // TODO (taproot|arik): move match into calling method for Taproot
-                       ChannelSignerType::Ecdsa(ecdsa) => {
-                               ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.context.secp_ctx)
-                                       .map(|(sig, _)| sig).ok()?
-                       },
-                       // TODO (taproot|arik)
-                       #[cfg(taproot)]
-                       _ => todo!()
-               };
-
-               if self.context.signer_pending_funding {
-                       log_trace!(logger, "Counterparty commitment signature ready for funding_created message: clearing signer_pending_funding");
-                       self.context.signer_pending_funding = false;
-               }
+               if self.context.signer_pending_funding {
+                       log_trace!(logger, "Counterparty commitment signature ready for funding_created message: clearing signer_pending_funding");
+                       self.context.signer_pending_funding = false;
+               }
 
                Some(msgs::FundingCreated {
                        temporary_channel_id: self.context.temporary_channel_id.unwrap(),
@@ -6425,7 +7394,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                // Now that we're past error-generating stuff, update our local state:
 
                self.context.channel_state = ChannelState::FundingNegotiated;
-               self.context.channel_id = funding_txo.to_channel_id();
+               self.context.channel_id = ChannelId::v1_from_funding_outpoint(funding_txo);
 
                // If the funding transaction is a coinbase transaction, we need to set the minimum depth to 100.
                // We can skip this if it is a zero-conf channel.
@@ -6440,38 +7409,20 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 
                let funding_created = self.get_funding_created_msg(logger);
                if funding_created.is_none() {
-                       if !self.context.signer_pending_funding {
-                               log_trace!(logger, "funding_created awaiting signer; setting signer_pending_funding");
-                               self.context.signer_pending_funding = true;
+                       #[cfg(not(async_signing))] {
+                               panic!("Failed to get signature for new funding creation");
+                       }
+                       #[cfg(async_signing)] {
+                               if !self.context.signer_pending_funding {
+                                       log_trace!(logger, "funding_created awaiting signer; setting signer_pending_funding");
+                                       self.context.signer_pending_funding = true;
+                               }
                        }
                }
 
                Ok(funding_created)
        }
 
-       fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures) -> ChannelTypeFeatures {
-               // The default channel type (ie the first one we try) depends on whether the channel is
-               // public - if it is, we just go with `only_static_remotekey` as it's the only option
-               // available. If it's private, we first try `scid_privacy` as it provides better privacy
-               // with no other changes, and fall back to `only_static_remotekey`.
-               let mut ret = ChannelTypeFeatures::only_static_remote_key();
-               if !config.channel_handshake_config.announced_channel &&
-                       config.channel_handshake_config.negotiate_scid_privacy &&
-                       their_features.supports_scid_privacy() {
-                       ret.set_scid_privacy_required();
-               }
-
-               // Optionally, if the user would like to negotiate the `anchors_zero_fee_htlc_tx` option, we
-               // set it now. If they don't understand it, we'll fall back to our default of
-               // `only_static_remotekey`.
-               if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx &&
-                       their_features.supports_anchors_zero_fee_htlc_tx() {
-                       ret.set_anchors_zero_fee_htlc_tx_required();
-               }
-
-               ret
-       }
-
        /// If we receive an error message, it may only be a rejection of the channel type we tried,
        /// not of our ability to open any channel at all. Thus, on error, we should first call this
        /// and see if we get a new `OpenChannel` message, otherwise the channel is failed.
@@ -6481,37 +7432,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
        where
                F::Target: FeeEstimator
        {
-               if !self.context.is_outbound() ||
-                       !matches!(
-                               self.context.channel_state, ChannelState::NegotiatingFunding(flags)
-                               if flags == NegotiatingFundingFlags::OUR_INIT_SENT
-                       )
-               {
-                       return Err(());
-               }
-               if self.context.channel_type == ChannelTypeFeatures::only_static_remote_key() {
-                       // We've exhausted our options
-                       return Err(());
-               }
-               // We support opening a few different types of channels. Try removing our additional
-               // features one by one until we've either arrived at our default or the counterparty has
-               // accepted one.
-               //
-               // Due to the order below, we may not negotiate `option_anchors_zero_fee_htlc_tx` if the
-               // counterparty doesn't support `option_scid_privacy`. Since `get_initial_channel_type`
-               // checks whether the counterparty supports every feature, this would only happen if the
-               // counterparty is advertising the feature, but rejecting channels proposing the feature for
-               // whatever reason.
-               if self.context.channel_type.supports_anchors_zero_fee_htlc_tx() {
-                       self.context.channel_type.clear_anchors_zero_fee_htlc_tx();
-                       self.context.feerate_per_kw = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
-                       assert!(!self.context.channel_transaction_parameters.channel_type_features.supports_anchors_nonzero_fee_htlc_tx());
-               } else if self.context.channel_type.supports_scid_privacy() {
-                       self.context.channel_type.clear_scid_privacy();
-               } else {
-                       self.context.channel_type = ChannelTypeFeatures::only_static_remote_key();
-               }
-               self.context.channel_transaction_parameters.channel_type_features = self.context.channel_type.clone();
+               self.context.maybe_downgrade_channel_features(fee_estimator)?;
                Ok(self.get_open_channel(chain_hash))
        }
 
@@ -6531,29 +7452,31 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                let keys = self.context.get_holder_pubkeys();
 
                msgs::OpenChannel {
-                       chain_hash,
-                       temporary_channel_id: self.context.channel_id,
-                       funding_satoshis: self.context.channel_value_satoshis,
+                       common_fields: msgs::CommonOpenChannelFields {
+                               chain_hash,
+                               temporary_channel_id: self.context.channel_id,
+                               funding_satoshis: self.context.channel_value_satoshis,
+                               dust_limit_satoshis: self.context.holder_dust_limit_satoshis,
+                               max_htlc_value_in_flight_msat: self.context.holder_max_htlc_value_in_flight_msat,
+                               htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
+                               commitment_feerate_sat_per_1000_weight: self.context.feerate_per_kw as u32,
+                               to_self_delay: self.context.get_holder_selected_contest_delay(),
+                               max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
+                               funding_pubkey: keys.funding_pubkey,
+                               revocation_basepoint: keys.revocation_basepoint.to_public_key(),
+                               payment_basepoint: keys.payment_point,
+                               delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
+                               htlc_basepoint: keys.htlc_basepoint.to_public_key(),
+                               first_per_commitment_point,
+                               channel_flags: if self.context.config.announced_channel {1} else {0},
+                               shutdown_scriptpubkey: Some(match &self.context.shutdown_scriptpubkey {
+                                       Some(script) => script.clone().into_inner(),
+                                       None => Builder::new().into_script(),
+                               }),
+                               channel_type: Some(self.context.channel_type.clone()),
+                       },
                        push_msat: self.context.channel_value_satoshis * 1000 - self.context.value_to_self_msat,
-                       dust_limit_satoshis: self.context.holder_dust_limit_satoshis,
-                       max_htlc_value_in_flight_msat: self.context.holder_max_htlc_value_in_flight_msat,
                        channel_reserve_satoshis: self.context.holder_selected_channel_reserve_satoshis,
-                       htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
-                       feerate_per_kw: self.context.feerate_per_kw as u32,
-                       to_self_delay: self.context.get_holder_selected_contest_delay(),
-                       max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
-                       funding_pubkey: keys.funding_pubkey,
-                       revocation_basepoint: keys.revocation_basepoint.to_public_key(),
-                       payment_point: keys.payment_point,
-                       delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
-                       htlc_basepoint: keys.htlc_basepoint.to_public_key(),
-                       first_per_commitment_point,
-                       channel_flags: if self.context.config.announced_channel {1} else {0},
-                       shutdown_scriptpubkey: Some(match &self.context.shutdown_scriptpubkey {
-                               Some(script) => script.clone().into_inner(),
-                               None => Builder::new().into_script(),
-                       }),
-                       channel_type: Some(self.context.channel_type.clone()),
                }
        }
 
@@ -6568,58 +7491,58 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                if !matches!(self.context.channel_state, ChannelState::NegotiatingFunding(flags) if flags == NegotiatingFundingFlags::OUR_INIT_SENT) {
                        return Err(ChannelError::Close("Got an accept_channel message at a strange time".to_owned()));
                }
-               if msg.dust_limit_satoshis > 21000000 * 100000000 {
-                       return Err(ChannelError::Close(format!("Peer never wants payout outputs? dust_limit_satoshis was {}", msg.dust_limit_satoshis)));
+               if msg.common_fields.dust_limit_satoshis > 21000000 * 100000000 {
+                       return Err(ChannelError::Close(format!("Peer never wants payout outputs? dust_limit_satoshis was {}", msg.common_fields.dust_limit_satoshis)));
                }
                if msg.channel_reserve_satoshis > self.context.channel_value_satoshis {
                        return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than ({})", msg.channel_reserve_satoshis, self.context.channel_value_satoshis)));
                }
-               if msg.dust_limit_satoshis > self.context.holder_selected_channel_reserve_satoshis {
-                       return Err(ChannelError::Close(format!("Dust limit ({}) is bigger than our channel reserve ({})", msg.dust_limit_satoshis, self.context.holder_selected_channel_reserve_satoshis)));
+               if msg.common_fields.dust_limit_satoshis > self.context.holder_selected_channel_reserve_satoshis {
+                       return Err(ChannelError::Close(format!("Dust limit ({}) is bigger than our channel reserve ({})", msg.common_fields.dust_limit_satoshis, self.context.holder_selected_channel_reserve_satoshis)));
                }
                if msg.channel_reserve_satoshis > self.context.channel_value_satoshis - self.context.holder_selected_channel_reserve_satoshis {
                        return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than channel value minus our reserve ({})",
                                msg.channel_reserve_satoshis, self.context.channel_value_satoshis - self.context.holder_selected_channel_reserve_satoshis)));
                }
                let full_channel_value_msat = (self.context.channel_value_satoshis - msg.channel_reserve_satoshis) * 1000;
-               if msg.htlc_minimum_msat >= full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) is full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
+               if msg.common_fields.htlc_minimum_msat >= full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) is full channel value ({})", msg.common_fields.htlc_minimum_msat, full_channel_value_msat)));
                }
                let max_delay_acceptable = u16::min(peer_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
-               if msg.to_self_delay > max_delay_acceptable {
-                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_delay_acceptable, msg.to_self_delay)));
+               if msg.common_fields.to_self_delay > max_delay_acceptable {
+                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_delay_acceptable, msg.common_fields.to_self_delay)));
                }
-               if msg.max_accepted_htlcs < 1 {
+               if msg.common_fields.max_accepted_htlcs < 1 {
                        return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
                }
-               if msg.max_accepted_htlcs > MAX_HTLCS {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.max_accepted_htlcs, MAX_HTLCS)));
+               if msg.common_fields.max_accepted_htlcs > MAX_HTLCS {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.common_fields.max_accepted_htlcs, MAX_HTLCS)));
                }
 
                // Now check against optional parameters as set by config...
-               if msg.htlc_minimum_msat > peer_limits.max_htlc_minimum_msat {
-                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat, peer_limits.max_htlc_minimum_msat)));
+               if msg.common_fields.htlc_minimum_msat > peer_limits.max_htlc_minimum_msat {
+                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.common_fields.htlc_minimum_msat, peer_limits.max_htlc_minimum_msat)));
                }
-               if msg.max_htlc_value_in_flight_msat < peer_limits.min_max_htlc_value_in_flight_msat {
-                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, peer_limits.min_max_htlc_value_in_flight_msat)));
+               if msg.common_fields.max_htlc_value_in_flight_msat < peer_limits.min_max_htlc_value_in_flight_msat {
+                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.common_fields.max_htlc_value_in_flight_msat, peer_limits.min_max_htlc_value_in_flight_msat)));
                }
                if msg.channel_reserve_satoshis > peer_limits.max_channel_reserve_satoshis {
                        return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, peer_limits.max_channel_reserve_satoshis)));
                }
-               if msg.max_accepted_htlcs < peer_limits.min_max_accepted_htlcs {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, peer_limits.min_max_accepted_htlcs)));
+               if msg.common_fields.max_accepted_htlcs < peer_limits.min_max_accepted_htlcs {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.common_fields.max_accepted_htlcs, peer_limits.min_max_accepted_htlcs)));
                }
-               if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
+               if msg.common_fields.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.common_fields.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
-               if msg.dust_limit_satoshis > MAX_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
+               if msg.common_fields.dust_limit_satoshis > MAX_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.common_fields.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
                }
-               if msg.minimum_depth > peer_limits.max_minimum_depth {
-                       return Err(ChannelError::Close(format!("We consider the minimum depth to be unreasonably large. Expected minimum: ({}). Actual: ({})", peer_limits.max_minimum_depth, msg.minimum_depth)));
+               if msg.common_fields.minimum_depth > peer_limits.max_minimum_depth {
+                       return Err(ChannelError::Close(format!("We consider the minimum depth to be unreasonably large. Expected minimum: ({}). Actual: ({})", peer_limits.max_minimum_depth, msg.common_fields.minimum_depth)));
                }
 
-               if let Some(ty) = &msg.channel_type {
+               if let Some(ty) = &msg.common_fields.channel_type {
                        if *ty != self.context.channel_type {
                                return Err(ChannelError::Close("Channel Type in accept_channel didn't match the one sent in open_channel.".to_owned()));
                        }
@@ -6635,7 +7558,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                }
 
                let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
-                       match &msg.shutdown_scriptpubkey {
+                       match &msg.common_fields.shutdown_scriptpubkey {
                                &Some(ref script) => {
                                        // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
                                        if script.len() == 0 {
@@ -6654,32 +7577,32 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                        }
                } else { None };
 
-               self.context.counterparty_dust_limit_satoshis = msg.dust_limit_satoshis;
-               self.context.counterparty_max_htlc_value_in_flight_msat = cmp::min(msg.max_htlc_value_in_flight_msat, self.context.channel_value_satoshis * 1000);
+               self.context.counterparty_dust_limit_satoshis = msg.common_fields.dust_limit_satoshis;
+               self.context.counterparty_max_htlc_value_in_flight_msat = cmp::min(msg.common_fields.max_htlc_value_in_flight_msat, self.context.channel_value_satoshis * 1000);
                self.context.counterparty_selected_channel_reserve_satoshis = Some(msg.channel_reserve_satoshis);
-               self.context.counterparty_htlc_minimum_msat = msg.htlc_minimum_msat;
-               self.context.counterparty_max_accepted_htlcs = msg.max_accepted_htlcs;
+               self.context.counterparty_htlc_minimum_msat = msg.common_fields.htlc_minimum_msat;
+               self.context.counterparty_max_accepted_htlcs = msg.common_fields.max_accepted_htlcs;
 
                if peer_limits.trust_own_funding_0conf {
-                       self.context.minimum_depth = Some(msg.minimum_depth);
+                       self.context.minimum_depth = Some(msg.common_fields.minimum_depth);
                } else {
-                       self.context.minimum_depth = Some(cmp::max(1, msg.minimum_depth));
+                       self.context.minimum_depth = Some(cmp::max(1, msg.common_fields.minimum_depth));
                }
 
                let counterparty_pubkeys = ChannelPublicKeys {
-                       funding_pubkey: msg.funding_pubkey,
-                       revocation_basepoint: RevocationBasepoint::from(msg.revocation_basepoint),
-                       payment_point: msg.payment_point,
-                       delayed_payment_basepoint: DelayedPaymentBasepoint::from(msg.delayed_payment_basepoint),
-                       htlc_basepoint: HtlcBasepoint::from(msg.htlc_basepoint)
+                       funding_pubkey: msg.common_fields.funding_pubkey,
+                       revocation_basepoint: RevocationBasepoint::from(msg.common_fields.revocation_basepoint),
+                       payment_point: msg.common_fields.payment_basepoint,
+                       delayed_payment_basepoint: DelayedPaymentBasepoint::from(msg.common_fields.delayed_payment_basepoint),
+                       htlc_basepoint: HtlcBasepoint::from(msg.common_fields.htlc_basepoint)
                };
 
                self.context.channel_transaction_parameters.counterparty_parameters = Some(CounterpartyChannelTransactionParameters {
-                       selected_contest_delay: msg.to_self_delay,
+                       selected_contest_delay: msg.common_fields.to_self_delay,
                        pubkeys: counterparty_pubkeys,
                });
 
-               self.context.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point);
+               self.context.counterparty_cur_commitment_point = Some(msg.common_fields.first_per_commitment_point);
                self.context.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey;
 
                self.context.channel_state = ChannelState::NegotiatingFunding(
@@ -6759,395 +7682,140 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                                                          &self.context.channel_transaction_parameters,
                                                          funding_redeemscript.clone(), self.context.channel_value_satoshis,
                                                          obscure_factor,
-                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
+                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id, self.context.channel_id());
                channel_monitor.provide_initial_counterparty_commitment_tx(
                        counterparty_initial_bitcoin_tx.txid, Vec::new(),
                        self.context.cur_counterparty_commitment_transaction_number,
-                       self.context.counterparty_cur_commitment_point.unwrap(),
-                       counterparty_initial_commitment_tx.feerate_per_kw(),
-                       counterparty_initial_commitment_tx.to_broadcaster_value_sat(),
-                       counterparty_initial_commitment_tx.to_countersignatory_value_sat(), logger);
-
-               assert!(!self.context.channel_state.is_monitor_update_in_progress()); // We have no had any monitor(s) yet to fail update!
-               if self.context.is_batch_funding() {
-                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::WAITING_FOR_BATCH);
-               } else {
-                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
-               }
-               self.context.cur_holder_commitment_transaction_number -= 1;
-               self.context.cur_counterparty_commitment_transaction_number -= 1;
-
-               log_info!(logger, "Received funding_signed from peer for channel {}", &self.context.channel_id());
-
-               let mut channel = Channel { context: self.context };
-
-               let need_channel_ready = channel.check_get_channel_ready(0).is_some();
-               channel.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
-               Ok((channel, channel_monitor))
-       }
-
-       /// Indicates that the signer may have some signatures for us, so we should retry if we're
-       /// blocked.
-       #[allow(unused)]
-       pub fn signer_maybe_unblocked<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
-               if self.context.signer_pending_funding && self.context.is_outbound() {
-                       log_trace!(logger, "Signer unblocked a funding_created");
-                       self.get_funding_created_msg(logger)
-               } else { None }
-       }
-}
-
-/// A not-yet-funded inbound (from counterparty) channel using V1 channel establishment.
-pub(super) struct InboundV1Channel<SP: Deref> where SP::Target: SignerProvider {
-       pub context: ChannelContext<SP>,
-       pub unfunded_context: UnfundedChannelContext,
-}
-
-impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
-       /// Creates a new channel from a remote sides' request for one.
-       /// Assumes chain_hash has already been checked and corresponds with what we expect!
-       pub fn new<ES: Deref, F: Deref, L: Deref>(
-               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
-               counterparty_node_id: PublicKey, our_supported_features: &ChannelTypeFeatures,
-               their_features: &InitFeatures, msg: &msgs::OpenChannel, user_id: u128, config: &UserConfig,
-               current_chain_height: u32, logger: &L, is_0conf: bool,
-       ) -> Result<InboundV1Channel<SP>, ChannelError>
-               where ES::Target: EntropySource,
-                         F::Target: FeeEstimator,
-                         L::Target: Logger,
-       {
-               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(msg.temporary_channel_id));
-               let announced_channel = if (msg.channel_flags & 1) == 1 { true } else { false };
-
-               // First check the channel type is known, failing before we do anything else if we don't
-               // support this channel type.
-               let channel_type = if let Some(channel_type) = &msg.channel_type {
-                       if channel_type.supports_any_optional_bits() {
-                               return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned()));
-                       }
-
-                       // We only support the channel types defined by the `ChannelManager` in
-                       // `provided_channel_type_features`. The channel type must always support
-                       // `static_remote_key`.
-                       if !channel_type.requires_static_remote_key() {
-                               return Err(ChannelError::Close("Channel Type was not understood - we require static remote key".to_owned()));
-                       }
-                       // Make sure we support all of the features behind the channel type.
-                       if !channel_type.is_subset(our_supported_features) {
-                               return Err(ChannelError::Close("Channel Type contains unsupported features".to_owned()));
-                       }
-                       if channel_type.requires_scid_privacy() && announced_channel {
-                               return Err(ChannelError::Close("SCID Alias/Privacy Channel Type cannot be set on a public channel".to_owned()));
-                       }
-                       channel_type.clone()
-               } else {
-                       let channel_type = ChannelTypeFeatures::from_init(&their_features);
-                       if channel_type != ChannelTypeFeatures::only_static_remote_key() {
-                               return Err(ChannelError::Close("Only static_remote_key is supported for non-negotiated channel types".to_owned()));
-                       }
-                       channel_type
-               };
-
-               let channel_keys_id = signer_provider.generate_channel_keys_id(true, msg.funding_satoshis, user_id);
-               let holder_signer = signer_provider.derive_channel_signer(msg.funding_satoshis, channel_keys_id);
-               let pubkeys = holder_signer.pubkeys().clone();
-               let counterparty_pubkeys = ChannelPublicKeys {
-                       funding_pubkey: msg.funding_pubkey,
-                       revocation_basepoint: RevocationBasepoint::from(msg.revocation_basepoint),
-                       payment_point: msg.payment_point,
-                       delayed_payment_basepoint: DelayedPaymentBasepoint::from(msg.delayed_payment_basepoint),
-                       htlc_basepoint: HtlcBasepoint::from(msg.htlc_basepoint)
-               };
-
-               if config.channel_handshake_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
-                       return Err(ChannelError::Close(format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks. It must be greater than {}", config.channel_handshake_config.our_to_self_delay, BREAKDOWN_TIMEOUT)));
-               }
-
-               // Check sanity of message fields:
-               if msg.funding_satoshis > config.channel_handshake_limits.max_funding_satoshis {
-                       return Err(ChannelError::Close(format!("Per our config, funding must be at most {}. It was {}", config.channel_handshake_limits.max_funding_satoshis, msg.funding_satoshis)));
-               }
-               if msg.funding_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
-                       return Err(ChannelError::Close(format!("Funding must be smaller than the total bitcoin supply. It was {}", msg.funding_satoshis)));
-               }
-               if msg.channel_reserve_satoshis > msg.funding_satoshis {
-                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must be not greater than funding_satoshis: {}", msg.channel_reserve_satoshis, msg.funding_satoshis)));
-               }
-               let full_channel_value_msat = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
-               if msg.push_msat > full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("push_msat {} was larger than channel amount minus reserve ({})", msg.push_msat, full_channel_value_msat)));
-               }
-               if msg.dust_limit_satoshis > msg.funding_satoshis {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis {} was larger than funding_satoshis {}. Peer never wants payout outputs?", msg.dust_limit_satoshis, msg.funding_satoshis)));
-               }
-               if msg.htlc_minimum_msat >= full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
-               }
-               Channel::<SP>::check_remote_fee(&channel_type, fee_estimator, msg.feerate_per_kw, None, &&logger)?;
-
-               let max_counterparty_selected_contest_delay = u16::min(config.channel_handshake_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
-               if msg.to_self_delay > max_counterparty_selected_contest_delay {
-                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_counterparty_selected_contest_delay, msg.to_self_delay)));
-               }
-               if msg.max_accepted_htlcs < 1 {
-                       return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
-               }
-               if msg.max_accepted_htlcs > MAX_HTLCS {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.max_accepted_htlcs, MAX_HTLCS)));
-               }
-
-               // Now check against optional parameters as set by config...
-               if msg.funding_satoshis < config.channel_handshake_limits.min_funding_satoshis {
-                       return Err(ChannelError::Close(format!("Funding satoshis ({}) is less than the user specified limit ({})", msg.funding_satoshis, config.channel_handshake_limits.min_funding_satoshis)));
-               }
-               if msg.htlc_minimum_msat > config.channel_handshake_limits.max_htlc_minimum_msat {
-                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat,  config.channel_handshake_limits.max_htlc_minimum_msat)));
-               }
-               if msg.max_htlc_value_in_flight_msat < config.channel_handshake_limits.min_max_htlc_value_in_flight_msat {
-                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, config.channel_handshake_limits.min_max_htlc_value_in_flight_msat)));
-               }
-               if msg.channel_reserve_satoshis > config.channel_handshake_limits.max_channel_reserve_satoshis {
-                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, config.channel_handshake_limits.max_channel_reserve_satoshis)));
-               }
-               if msg.max_accepted_htlcs < config.channel_handshake_limits.min_max_accepted_htlcs {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.channel_handshake_limits.min_max_accepted_htlcs)));
-               }
-               if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
-               }
-               if msg.dust_limit_satoshis >  MAX_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
-               }
-
-               // Convert things into internal flags and prep our state:
-
-               if config.channel_handshake_limits.force_announced_channel_preference {
-                       if config.channel_handshake_config.announced_channel != announced_channel {
-                               return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours".to_owned()));
-                       }
-               }
-
-               let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis, config);
-               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       // Protocol level safety check in place, although it should never happen because
-                       // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
-                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
-               }
-               if holder_selected_channel_reserve_satoshis * 1000 >= full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({})msats. Channel value is ({} - {})msats.", holder_selected_channel_reserve_satoshis * 1000, full_channel_value_msat, msg.push_msat)));
-               }
-               if msg.channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       log_debug!(logger, "channel_reserve_satoshis ({}) is smaller than our dust limit ({}). We can broadcast stale states without any risk, implying this channel is very insecure for our counterparty.",
-                               msg.channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
-               }
-               if holder_selected_channel_reserve_satoshis < msg.dust_limit_satoshis {
-                       return Err(ChannelError::Close(format!("Dust limit ({}) too high for the channel reserve we require the remote to keep ({})", msg.dust_limit_satoshis, holder_selected_channel_reserve_satoshis)));
-               }
-
-               // check if the funder's amount for the initial commitment tx is sufficient
-               // for full fee payment plus a few HTLCs to ensure the channel will be useful.
-               let anchor_outputs_value = if channel_type.supports_anchors_zero_fee_htlc_tx() {
-                       ANCHOR_OUTPUT_VALUE_SATOSHI * 2
-               } else {
-                       0
-               };
-               let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat;
-               let commitment_tx_fee = commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT, &channel_type) / 1000;
-               if (funders_amount_msat / 1000).saturating_sub(anchor_outputs_value) < commitment_tx_fee {
-                       return Err(ChannelError::Close(format!("Funding amount ({} sats) can't even pay fee for initial commitment transaction fee of {} sats.", (funders_amount_msat / 1000).saturating_sub(anchor_outputs_value), commitment_tx_fee)));
-               }
-
-               let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee - anchor_outputs_value;
-               // While it's reasonable for us to not meet the channel reserve initially (if they don't
-               // want to push much to us), our counterparty should always have more than our reserve.
-               if to_remote_satoshis < holder_selected_channel_reserve_satoshis {
-                       return Err(ChannelError::Close("Insufficient funding amount for initial reserve".to_owned()));
-               }
-
-               let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
-                       match &msg.shutdown_scriptpubkey {
-                               &Some(ref script) => {
-                                       // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
-                                       if script.len() == 0 {
-                                               None
-                                       } else {
-                                               if !script::is_bolt2_compliant(&script, their_features) {
-                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)))
-                                               }
-                                               Some(script.clone())
-                                       }
-                               },
-                               // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
-                               &None => {
-                                       return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out".to_owned()));
-                               }
-                       }
-               } else { None };
-
-               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
-                       match signer_provider.get_shutdown_scriptpubkey() {
-                               Ok(scriptpubkey) => Some(scriptpubkey),
-                               Err(_) => return Err(ChannelError::Close("Failed to get upfront shutdown scriptpubkey".to_owned())),
-                       }
-               } else { None };
-
-               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
-                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
-                               return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
-                       }
-               }
-
-               let destination_script = match signer_provider.get_destination_script(channel_keys_id) {
-                       Ok(script) => script,
-                       Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())),
-               };
-
-               let mut secp_ctx = Secp256k1::new();
-               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
-
-               let minimum_depth = if is_0conf {
-                       Some(0)
-               } else {
-                       Some(cmp::max(config.channel_handshake_config.minimum_depth, 1))
-               };
-
-               let chan = Self {
-                       context: ChannelContext {
-                               user_id,
-
-                               config: LegacyChannelConfig {
-                                       options: config.channel_config.clone(),
-                                       announced_channel,
-                                       commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
-                               },
-
-                               prev_config: None,
-
-                               inbound_handshake_limits_override: None,
-
-                               temporary_channel_id: Some(msg.temporary_channel_id),
-                               channel_id: msg.temporary_channel_id,
-                               channel_state: ChannelState::NegotiatingFunding(
-                                       NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT
-                               ),
-                               announcement_sigs_state: AnnouncementSigsState::NotSent,
-                               secp_ctx,
+                       self.context.counterparty_cur_commitment_point.unwrap(),
+                       counterparty_initial_commitment_tx.feerate_per_kw(),
+                       counterparty_initial_commitment_tx.to_broadcaster_value_sat(),
+                       counterparty_initial_commitment_tx.to_countersignatory_value_sat(), logger);
 
-                               latest_monitor_update_id: 0,
+               assert!(!self.context.channel_state.is_monitor_update_in_progress()); // We have no had any monitor(s) yet to fail update!
+               if self.context.is_batch_funding() {
+                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::WAITING_FOR_BATCH);
+               } else {
+                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
+               }
+               self.context.cur_holder_commitment_transaction_number -= 1;
+               self.context.cur_counterparty_commitment_transaction_number -= 1;
 
-                               holder_signer: ChannelSignerType::Ecdsa(holder_signer),
-                               shutdown_scriptpubkey,
-                               destination_script,
+               log_info!(logger, "Received funding_signed from peer for channel {}", &self.context.channel_id());
 
-                               cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               value_to_self_msat: msg.push_msat,
+               let mut channel = Channel {
+                       context: self.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       dual_funding_channel_context: None,
+               };
 
-                               pending_inbound_htlcs: Vec::new(),
-                               pending_outbound_htlcs: Vec::new(),
-                               holding_cell_htlc_updates: Vec::new(),
-                               pending_update_fee: None,
-                               holding_cell_update_fee: None,
-                               next_holder_htlc_id: 0,
-                               next_counterparty_htlc_id: 0,
-                               update_time_counter: 1,
+               let need_channel_ready = channel.check_get_channel_ready(0).is_some();
+               channel.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
+               Ok((channel, channel_monitor))
+       }
 
-                               resend_order: RAACommitmentOrder::CommitmentFirst,
+       /// Indicates that the signer may have some signatures for us, so we should retry if we're
+       /// blocked.
+       #[cfg(async_signing)]
+       pub fn signer_maybe_unblocked<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
+               if self.context.signer_pending_funding && self.context.is_outbound() {
+                       log_trace!(logger, "Signer unblocked a funding_created");
+                       self.get_funding_created_msg(logger)
+               } else { None }
+       }
+}
 
-                               monitor_pending_channel_ready: false,
-                               monitor_pending_revoke_and_ack: false,
-                               monitor_pending_commitment_signed: false,
-                               monitor_pending_forwards: Vec::new(),
-                               monitor_pending_failures: Vec::new(),
-                               monitor_pending_finalized_fulfills: Vec::new(),
+/// A not-yet-funded inbound (from counterparty) channel using V1 channel establishment.
+pub(super) struct InboundV1Channel<SP: Deref> where SP::Target: SignerProvider {
+       pub context: ChannelContext<SP>,
+       pub unfunded_context: UnfundedChannelContext,
+}
 
-                               signer_pending_commitment_update: false,
-                               signer_pending_funding: false,
+/// Fetches the [`ChannelTypeFeatures`] that will be used for a channel built from a given
+/// [`msgs::CommonOpenChannelFields`].
+pub(super) fn channel_type_from_open_channel(
+       common_fields: &msgs::CommonOpenChannelFields, their_features: &InitFeatures,
+       our_supported_features: &ChannelTypeFeatures
+) -> Result<ChannelTypeFeatures, ChannelError> {
+       if let Some(channel_type) = &common_fields.channel_type {
+               if channel_type.supports_any_optional_bits() {
+                       return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned()));
+               }
 
-                               #[cfg(debug_assertions)]
-                               holder_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
-                               #[cfg(debug_assertions)]
-                               counterparty_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+               // We only support the channel types defined by the `ChannelManager` in
+               // `provided_channel_type_features`. The channel type must always support
+               // `static_remote_key`.
+               if !channel_type.requires_static_remote_key() {
+                       return Err(ChannelError::Close("Channel Type was not understood - we require static remote key".to_owned()));
+               }
+               // Make sure we support all of the features behind the channel type.
+               if !channel_type.is_subset(our_supported_features) {
+                       return Err(ChannelError::Close("Channel Type contains unsupported features".to_owned()));
+               }
+               let announced_channel = if (common_fields.channel_flags & 1) == 1 { true } else { false };
+               if channel_type.requires_scid_privacy() && announced_channel {
+                       return Err(ChannelError::Close("SCID Alias/Privacy Channel Type cannot be set on a public channel".to_owned()));
+               }
+               Ok(channel_type.clone())
+       } else {
+               let channel_type = ChannelTypeFeatures::from_init(&their_features);
+               if channel_type != ChannelTypeFeatures::only_static_remote_key() {
+                       return Err(ChannelError::Close("Only static_remote_key is supported for non-negotiated channel types".to_owned()));
+               }
+               Ok(channel_type)
+       }
+}
 
-                               last_sent_closing_fee: None,
-                               pending_counterparty_closing_signed: None,
-                               expecting_peer_commitment_signed: false,
-                               closing_fee_limits: None,
-                               target_closing_feerate_sats_per_kw: None,
-
-                               funding_tx_confirmed_in: None,
-                               funding_tx_confirmation_height: 0,
-                               short_channel_id: None,
-                               channel_creation_height: current_chain_height,
-
-                               feerate_per_kw: msg.feerate_per_kw,
-                               channel_value_satoshis: msg.funding_satoshis,
-                               counterparty_dust_limit_satoshis: msg.dust_limit_satoshis,
-                               holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
-                               counterparty_max_htlc_value_in_flight_msat: cmp::min(msg.max_htlc_value_in_flight_msat, msg.funding_satoshis * 1000),
-                               holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(msg.funding_satoshis, &config.channel_handshake_config),
-                               counterparty_selected_channel_reserve_satoshis: Some(msg.channel_reserve_satoshis),
-                               holder_selected_channel_reserve_satoshis,
-                               counterparty_htlc_minimum_msat: msg.htlc_minimum_msat,
-                               holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
-                               counterparty_max_accepted_htlcs: msg.max_accepted_htlcs,
-                               holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
-                               minimum_depth,
+impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
+       /// Creates a new channel from a remote sides' request for one.
+       /// Assumes chain_hash has already been checked and corresponds with what we expect!
+       pub fn new<ES: Deref, F: Deref, L: Deref>(
+               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
+               counterparty_node_id: PublicKey, our_supported_features: &ChannelTypeFeatures,
+               their_features: &InitFeatures, msg: &msgs::OpenChannel, user_id: u128, config: &UserConfig,
+               current_chain_height: u32, logger: &L, is_0conf: bool,
+       ) -> Result<InboundV1Channel<SP>, ChannelError>
+               where ES::Target: EntropySource,
+                         F::Target: FeeEstimator,
+                         L::Target: Logger,
+       {
+               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(msg.common_fields.temporary_channel_id));
 
-                               counterparty_forwarding_info: None,
+               // First check the channel type is known, failing before we do anything else if we don't
+               // support this channel type.
+               let channel_type = channel_type_from_open_channel(&msg.common_fields, their_features, our_supported_features)?;
 
-                               channel_transaction_parameters: ChannelTransactionParameters {
-                                       holder_pubkeys: pubkeys,
-                                       holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
-                                       is_outbound_from_holder: false,
-                                       counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
-                                               selected_contest_delay: msg.to_self_delay,
-                                               pubkeys: counterparty_pubkeys,
-                                       }),
-                                       funding_outpoint: None,
-                                       channel_type_features: channel_type.clone()
-                               },
-                               funding_transaction: None,
-                               is_batch_funding: None,
+               let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(msg.common_fields.funding_satoshis, config);
+               let counterparty_pubkeys = ChannelPublicKeys {
+                       funding_pubkey: msg.common_fields.funding_pubkey,
+                       revocation_basepoint: RevocationBasepoint::from(msg.common_fields.revocation_basepoint),
+                       payment_point: msg.common_fields.payment_basepoint,
+                       delayed_payment_basepoint: DelayedPaymentBasepoint::from(msg.common_fields.delayed_payment_basepoint),
+                       htlc_basepoint: HtlcBasepoint::from(msg.common_fields.htlc_basepoint)
+               };
 
-                               counterparty_cur_commitment_point: Some(msg.first_per_commitment_point),
-                               counterparty_prev_commitment_point: None,
+               let chan = Self {
+                       context: ChannelContext::new_for_inbound_channel(
+                               fee_estimator,
+                               entropy_source,
+                               signer_provider,
                                counterparty_node_id,
+                               their_features,
+                               user_id,
+                               config,
+                               current_chain_height,
+                               &&logger,
+                               is_0conf,
+                               0,
 
-                               counterparty_shutdown_scriptpubkey,
-
-                               commitment_secrets: CounterpartyCommitmentSecrets::new(),
-
-                               channel_update_status: ChannelUpdateStatus::Enabled,
-                               closing_signed_in_flight: false,
-
-                               announcement_sigs: None,
-
-                               #[cfg(any(test, fuzzing))]
-                               next_local_commitment_tx_fee_info_cached: Mutex::new(None),
-                               #[cfg(any(test, fuzzing))]
-                               next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
-
-                               workaround_lnd_bug_4006: None,
-                               sent_message_awaiting_response: None,
-
-                               latest_inbound_scid_alias: None,
-                               outbound_scid_alias: 0,
-
-                               channel_pending_event_emitted: false,
-                               channel_ready_event_emitted: false,
-
-                               #[cfg(any(test, fuzzing))]
-                               historical_inbound_htlc_fulfills: HashSet::new(),
-
+                               counterparty_pubkeys,
                                channel_type,
-                               channel_keys_id,
-
-                               blocked_monitor_updates: Vec::new(),
-                       },
+                               holder_selected_channel_reserve_satoshis,
+                               msg.channel_reserve_satoshis,
+                               msg.push_msat,
+                               msg.common_fields.clone(),
+                       )?,
                        unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 }
                };
-
                Ok(chan)
        }
 
@@ -7182,25 +7850,27 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                let keys = self.context.get_holder_pubkeys();
 
                msgs::AcceptChannel {
-                       temporary_channel_id: self.context.channel_id,
-                       dust_limit_satoshis: self.context.holder_dust_limit_satoshis,
-                       max_htlc_value_in_flight_msat: self.context.holder_max_htlc_value_in_flight_msat,
+                       common_fields: msgs::CommonAcceptChannelFields {
+                               temporary_channel_id: self.context.channel_id,
+                               dust_limit_satoshis: self.context.holder_dust_limit_satoshis,
+                               max_htlc_value_in_flight_msat: self.context.holder_max_htlc_value_in_flight_msat,
+                               htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
+                               minimum_depth: self.context.minimum_depth.unwrap(),
+                               to_self_delay: self.context.get_holder_selected_contest_delay(),
+                               max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
+                               funding_pubkey: keys.funding_pubkey,
+                               revocation_basepoint: keys.revocation_basepoint.to_public_key(),
+                               payment_basepoint: keys.payment_point,
+                               delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
+                               htlc_basepoint: keys.htlc_basepoint.to_public_key(),
+                               first_per_commitment_point,
+                               shutdown_scriptpubkey: Some(match &self.context.shutdown_scriptpubkey {
+                                       Some(script) => script.clone().into_inner(),
+                                       None => Builder::new().into_script(),
+                               }),
+                               channel_type: Some(self.context.channel_type.clone()),
+                       },
                        channel_reserve_satoshis: self.context.holder_selected_channel_reserve_satoshis,
-                       htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
-                       minimum_depth: self.context.minimum_depth.unwrap(),
-                       to_self_delay: self.context.get_holder_selected_contest_delay(),
-                       max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
-                       funding_pubkey: keys.funding_pubkey,
-                       revocation_basepoint: keys.revocation_basepoint.to_public_key(),
-                       payment_point: keys.payment_point,
-                       delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
-                       htlc_basepoint: keys.htlc_basepoint.to_public_key(),
-                       first_per_commitment_point,
-                       shutdown_scriptpubkey: Some(match &self.context.shutdown_scriptpubkey {
-                               Some(script) => script.clone().into_inner(),
-                               None => Builder::new().into_script(),
-                       }),
-                       channel_type: Some(self.context.channel_type.clone()),
                        #[cfg(taproot)]
                        next_local_nonce: None,
                }
@@ -7291,7 +7961,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                // Now that we're past error-generating stuff, update our local state:
 
                self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
-               self.context.channel_id = funding_txo.to_channel_id();
+               self.context.channel_id = ChannelId::v1_from_funding_outpoint(funding_txo);
                self.context.cur_counterparty_commitment_transaction_number -= 1;
                self.context.cur_holder_commitment_transaction_number -= 1;
 
@@ -7309,7 +7979,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                                                          &self.context.channel_transaction_parameters,
                                                          funding_redeemscript.clone(), self.context.channel_value_satoshis,
                                                          obscure_factor,
-                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
+                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id, self.context.channel_id());
                channel_monitor.provide_initial_counterparty_commitment_tx(
                        counterparty_initial_commitment_tx.trust().txid(), Vec::new(),
                        self.context.cur_counterparty_commitment_transaction_number + 1,
@@ -7324,6 +7994,8 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                // `ChannelMonitor`.
                let mut channel = Channel {
                        context: self.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       dual_funding_channel_context: None,
                };
                let need_channel_ready = channel.check_get_channel_ready(0).is_some();
                channel.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
@@ -7332,7 +8004,310 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
        }
 }
 
-const SERIALIZATION_VERSION: u8 = 3;
+// A not-yet-funded outbound (from holder) channel using V2 channel establishment.
+#[cfg(any(dual_funding, splicing))]
+pub(super) struct OutboundV2Channel<SP: Deref> where SP::Target: SignerProvider {
+       pub context: ChannelContext<SP>,
+       pub unfunded_context: UnfundedChannelContext,
+       #[cfg(any(dual_funding, splicing))]
+       pub dual_funding_context: DualFundingChannelContext,
+}
+
+#[cfg(any(dual_funding, splicing))]
+impl<SP: Deref> OutboundV2Channel<SP> where SP::Target: SignerProvider {
+       pub fn new<ES: Deref, F: Deref>(
+               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
+               counterparty_node_id: PublicKey, their_features: &InitFeatures, funding_satoshis: u64,
+               user_id: u128, config: &UserConfig, current_chain_height: u32, outbound_scid_alias: u64,
+               funding_confirmation_target: ConfirmationTarget,
+       ) -> Result<OutboundV2Channel<SP>, APIError>
+       where ES::Target: EntropySource,
+             F::Target: FeeEstimator,
+       {
+               let channel_keys_id = signer_provider.generate_channel_keys_id(false, funding_satoshis, user_id);
+               let holder_signer = signer_provider.derive_channel_signer(funding_satoshis, channel_keys_id);
+               let pubkeys = holder_signer.pubkeys().clone();
+
+               let temporary_channel_id = Some(ChannelId::temporary_v2_from_revocation_basepoint(&pubkeys.revocation_basepoint));
+
+               let holder_selected_channel_reserve_satoshis = get_v2_channel_reserve_satoshis(
+                       funding_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
+
+               let funding_feerate_sat_per_1000_weight = fee_estimator.bounded_sat_per_1000_weight(funding_confirmation_target);
+               let funding_tx_locktime = current_chain_height;
+
+               let chan = Self {
+                       context: ChannelContext::new_for_outbound_channel(
+                               fee_estimator,
+                               entropy_source,
+                               signer_provider,
+                               counterparty_node_id,
+                               their_features,
+                               funding_satoshis,
+                               0,
+                               user_id,
+                               config,
+                               current_chain_height,
+                               outbound_scid_alias,
+                               temporary_channel_id,
+                               holder_selected_channel_reserve_satoshis,
+                               channel_keys_id,
+                               holder_signer,
+                               pubkeys,
+                       )?,
+                       unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 },
+                       dual_funding_context: DualFundingChannelContext {
+                               our_funding_satoshis: funding_satoshis,
+                               their_funding_satoshis: 0,
+                               funding_tx_locktime,
+                               funding_feerate_sat_per_1000_weight,
+                       }
+               };
+               Ok(chan)
+       }
+
+       /// If we receive an error message, it may only be a rejection of the channel type we tried,
+       /// not of our ability to open any channel at all. Thus, on error, we should first call this
+       /// and see if we get a new `OpenChannelV2` message, otherwise the channel is failed.
+       pub(crate) fn maybe_handle_error_without_close<F: Deref>(
+               &mut self, chain_hash: ChainHash, fee_estimator: &LowerBoundedFeeEstimator<F>
+       ) -> Result<msgs::OpenChannelV2, ()>
+       where
+               F::Target: FeeEstimator
+       {
+               self.context.maybe_downgrade_channel_features(fee_estimator)?;
+               Ok(self.get_open_channel_v2(chain_hash))
+       }
+
+       pub fn get_open_channel_v2(&self, chain_hash: ChainHash) -> msgs::OpenChannelV2 {
+               if self.context.have_received_message() {
+                       debug_assert!(false, "Cannot generate an open_channel2 after we've moved forward");
+               }
+
+               if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                       debug_assert!(false, "Tried to send an open_channel2 for a channel that has already advanced");
+               }
+
+               let first_per_commitment_point = self.context.holder_signer.as_ref()
+                       .get_per_commitment_point(self.context.cur_holder_commitment_transaction_number,
+                               &self.context.secp_ctx);
+               let second_per_commitment_point = self.context.holder_signer.as_ref()
+                       .get_per_commitment_point(self.context.cur_holder_commitment_transaction_number - 1,
+                               &self.context.secp_ctx);
+               let keys = self.context.get_holder_pubkeys();
+
+               msgs::OpenChannelV2 {
+                       common_fields: msgs::CommonOpenChannelFields {
+                               chain_hash,
+                               temporary_channel_id: self.context.temporary_channel_id.unwrap(),
+                               funding_satoshis: self.context.channel_value_satoshis,
+                               dust_limit_satoshis: self.context.holder_dust_limit_satoshis,
+                               max_htlc_value_in_flight_msat: self.context.holder_max_htlc_value_in_flight_msat,
+                               htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
+                               commitment_feerate_sat_per_1000_weight: self.context.feerate_per_kw,
+                               to_self_delay: self.context.get_holder_selected_contest_delay(),
+                               max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
+                               funding_pubkey: keys.funding_pubkey,
+                               revocation_basepoint: keys.revocation_basepoint.to_public_key(),
+                               payment_basepoint: keys.payment_point,
+                               delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
+                               htlc_basepoint: keys.htlc_basepoint.to_public_key(),
+                               first_per_commitment_point,
+                               channel_flags: if self.context.config.announced_channel {1} else {0},
+                               shutdown_scriptpubkey: Some(match &self.context.shutdown_scriptpubkey {
+                                       Some(script) => script.clone().into_inner(),
+                                       None => Builder::new().into_script(),
+                               }),
+                               channel_type: Some(self.context.channel_type.clone()),
+                       },
+                       funding_feerate_sat_per_1000_weight: self.context.feerate_per_kw,
+                       second_per_commitment_point,
+                       locktime: self.dual_funding_context.funding_tx_locktime,
+                       require_confirmed_inputs: None,
+               }
+       }
+}
+
+// A not-yet-funded inbound (from counterparty) channel using V2 channel establishment.
+#[cfg(any(dual_funding, splicing))]
+pub(super) struct InboundV2Channel<SP: Deref> where SP::Target: SignerProvider {
+       pub context: ChannelContext<SP>,
+       pub unfunded_context: UnfundedChannelContext,
+       pub dual_funding_context: DualFundingChannelContext,
+}
+
+#[cfg(any(dual_funding, splicing))]
+impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
+       /// Creates a new dual-funded channel from a remote side's request for one.
+       /// Assumes chain_hash has already been checked and corresponds with what we expect!
+       pub fn new<ES: Deref, F: Deref, L: Deref>(
+               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
+               counterparty_node_id: PublicKey, our_supported_features: &ChannelTypeFeatures,
+               their_features: &InitFeatures, msg: &msgs::OpenChannelV2, funding_satoshis: u64, user_id: u128,
+               config: &UserConfig, current_chain_height: u32, logger: &L,
+       ) -> Result<InboundV2Channel<SP>, ChannelError>
+               where ES::Target: EntropySource,
+                         F::Target: FeeEstimator,
+                         L::Target: Logger,
+       {
+               let channel_value_satoshis = funding_satoshis.saturating_add(msg.common_fields.funding_satoshis);
+               let counterparty_selected_channel_reserve_satoshis = get_v2_channel_reserve_satoshis(
+                       channel_value_satoshis, msg.common_fields.dust_limit_satoshis);
+               let holder_selected_channel_reserve_satoshis = get_v2_channel_reserve_satoshis(
+                       channel_value_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
+
+               // First check the channel type is known, failing before we do anything else if we don't
+               // support this channel type.
+               if msg.common_fields.channel_type.is_none() {
+                       return Err(ChannelError::Close(format!("Rejecting V2 channel {} missing channel_type",
+                               msg.common_fields.temporary_channel_id)))
+               }
+               let channel_type = channel_type_from_open_channel(&msg.common_fields, their_features, our_supported_features)?;
+
+               let counterparty_pubkeys = ChannelPublicKeys {
+                       funding_pubkey: msg.common_fields.funding_pubkey,
+                       revocation_basepoint: RevocationBasepoint(msg.common_fields.revocation_basepoint),
+                       payment_point: msg.common_fields.payment_basepoint,
+                       delayed_payment_basepoint: DelayedPaymentBasepoint(msg.common_fields.delayed_payment_basepoint),
+                       htlc_basepoint: HtlcBasepoint(msg.common_fields.htlc_basepoint)
+               };
+
+               let mut context = ChannelContext::new_for_inbound_channel(
+                       fee_estimator,
+                       entropy_source,
+                       signer_provider,
+                       counterparty_node_id,
+                       their_features,
+                       user_id,
+                       config,
+                       current_chain_height,
+                       logger,
+                       false,
+
+                       funding_satoshis,
+
+                       counterparty_pubkeys,
+                       channel_type,
+                       holder_selected_channel_reserve_satoshis,
+                       counterparty_selected_channel_reserve_satoshis,
+                       0 /* push_msat not used in dual-funding */,
+                       msg.common_fields.clone(),
+               )?;
+               let channel_id = ChannelId::v2_from_revocation_basepoints(
+                       &context.get_holder_pubkeys().revocation_basepoint,
+                       &context.get_counterparty_pubkeys().revocation_basepoint);
+               context.channel_id = channel_id;
+
+               let chan = Self {
+                       context,
+                       unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 },
+                       dual_funding_context: DualFundingChannelContext {
+                               our_funding_satoshis: funding_satoshis,
+                               their_funding_satoshis: msg.common_fields.funding_satoshis,
+                               funding_tx_locktime: msg.locktime,
+                               funding_feerate_sat_per_1000_weight: msg.funding_feerate_sat_per_1000_weight,
+                       }
+               };
+
+               Ok(chan)
+       }
+
+       /// Marks an inbound channel as accepted and generates a [`msgs::AcceptChannelV2`] message which
+       /// should be sent back to the counterparty node.
+       ///
+       /// [`msgs::AcceptChannelV2`]: crate::ln::msgs::AcceptChannelV2
+       pub fn accept_inbound_dual_funded_channel(&mut self) -> msgs::AcceptChannelV2 {
+               if self.context.is_outbound() {
+                       debug_assert!(false, "Tried to send accept_channel for an outbound channel?");
+               }
+               if !matches!(
+                       self.context.channel_state, ChannelState::NegotiatingFunding(flags)
+                       if flags == (NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT)
+               ) {
+                       debug_assert!(false, "Tried to send accept_channel2 after channel had moved forward");
+               }
+               if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                       debug_assert!(false, "Tried to send an accept_channel2 for a channel that has already advanced");
+               }
+
+               self.generate_accept_channel_v2_message()
+       }
+
+       /// This function is used to explicitly generate a [`msgs::AcceptChannel`] message for an
+       /// inbound channel. If the intention is to accept an inbound channel, use
+       /// [`InboundV1Channel::accept_inbound_channel`] instead.
+       ///
+       /// [`msgs::AcceptChannelV2`]: crate::ln::msgs::AcceptChannelV2
+       fn generate_accept_channel_v2_message(&self) -> msgs::AcceptChannelV2 {
+               let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(
+                       self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
+               let second_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(
+                       self.context.cur_holder_commitment_transaction_number - 1, &self.context.secp_ctx);
+               let keys = self.context.get_holder_pubkeys();
+
+               msgs::AcceptChannelV2 {
+                       common_fields: msgs::CommonAcceptChannelFields {
+                               temporary_channel_id: self.context.temporary_channel_id.unwrap(),
+                               dust_limit_satoshis: self.context.holder_dust_limit_satoshis,
+                               max_htlc_value_in_flight_msat: self.context.holder_max_htlc_value_in_flight_msat,
+                               htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
+                               minimum_depth: self.context.minimum_depth.unwrap(),
+                               to_self_delay: self.context.get_holder_selected_contest_delay(),
+                               max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
+                               funding_pubkey: keys.funding_pubkey,
+                               revocation_basepoint: keys.revocation_basepoint.to_public_key(),
+                               payment_basepoint: keys.payment_point,
+                               delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
+                               htlc_basepoint: keys.htlc_basepoint.to_public_key(),
+                               first_per_commitment_point,
+                               shutdown_scriptpubkey: Some(match &self.context.shutdown_scriptpubkey {
+                                       Some(script) => script.clone().into_inner(),
+                                       None => Builder::new().into_script(),
+                               }),
+                               channel_type: Some(self.context.channel_type.clone()),
+                       },
+                       funding_satoshis: self.dual_funding_context.our_funding_satoshis,
+                       second_per_commitment_point,
+                       require_confirmed_inputs: None,
+               }
+       }
+
+       /// Enables the possibility for tests to extract a [`msgs::AcceptChannelV2`] message for an
+       /// inbound channel without accepting it.
+       ///
+       /// [`msgs::AcceptChannelV2`]: crate::ln::msgs::AcceptChannelV2
+       #[cfg(test)]
+       pub fn get_accept_channel_v2_message(&self) -> msgs::AcceptChannelV2 {
+               self.generate_accept_channel_v2_message()
+       }
+}
+
+// Unfunded channel utilities
+
+fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures) -> ChannelTypeFeatures {
+       // The default channel type (ie the first one we try) depends on whether the channel is
+       // public - if it is, we just go with `only_static_remotekey` as it's the only option
+       // available. If it's private, we first try `scid_privacy` as it provides better privacy
+       // with no other changes, and fall back to `only_static_remotekey`.
+       let mut ret = ChannelTypeFeatures::only_static_remote_key();
+       if !config.channel_handshake_config.announced_channel &&
+               config.channel_handshake_config.negotiate_scid_privacy &&
+               their_features.supports_scid_privacy() {
+               ret.set_scid_privacy_required();
+       }
+
+       // Optionally, if the user would like to negotiate the `anchors_zero_fee_htlc_tx` option, we
+       // set it now. If they don't understand it, we'll fall back to our default of
+       // `only_static_remotekey`.
+       if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx &&
+               their_features.supports_anchors_zero_fee_htlc_tx() {
+               ret.set_anchors_zero_fee_htlc_tx_required();
+       }
+
+       ret
+}
+
+const SERIALIZATION_VERSION: u8 = 4;
 const MIN_SERIALIZATION_VERSION: u8 = 3;
 
 impl_writeable_tlv_based_enum!(InboundHTLCRemovalReason,;
@@ -7394,7 +8369,18 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                // Note that we write out as if remove_uncommitted_htlcs_and_mark_paused had just been
                // called.
 
-               write_ver_prefix!(writer, MIN_SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
+               let version_to_write = if self.context.pending_inbound_htlcs.iter().any(|htlc| match htlc.state {
+                       InboundHTLCState::AwaitingRemoteRevokeToAnnounce(ref htlc_resolution)|
+                               InboundHTLCState::AwaitingAnnouncedRemoteRevoke(ref htlc_resolution) => {
+                               matches!(htlc_resolution, InboundHTLCResolution::Pending { .. })
+                       },
+                       _ => false,
+               }) {
+                       SERIALIZATION_VERSION
+               } else {
+                       MIN_SERIALIZATION_VERSION
+               };
+               write_ver_prefix!(writer, version_to_write, MIN_SERIALIZATION_VERSION);
 
                // `user_id` used to be a single u64 value. In order to remain backwards compatible with
                // versions prior to 0.0.113, the u128 is serialized as two separate u64 values. We write
@@ -7412,6 +8398,8 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        let mut channel_state = self.context.channel_state;
                        if matches!(channel_state, ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_)) {
                                channel_state.set_peer_disconnected();
+                       } else {
+                               debug_assert!(false, "Pre-funded/shutdown channels should not be written");
                        }
                        channel_state.to_u32().write(writer)?;
                }
@@ -7448,13 +8436,29 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        htlc.payment_hash.write(writer)?;
                        match &htlc.state {
                                &InboundHTLCState::RemoteAnnounced(_) => unreachable!(),
-                               &InboundHTLCState::AwaitingRemoteRevokeToAnnounce(ref htlc_state) => {
+                               &InboundHTLCState::AwaitingRemoteRevokeToAnnounce(ref htlc_resolution) => {
                                        1u8.write(writer)?;
-                                       htlc_state.write(writer)?;
+                                       if version_to_write <= 3 {
+                                               if let InboundHTLCResolution::Resolved { pending_htlc_status } = htlc_resolution {
+                                                       pending_htlc_status.write(writer)?;
+                                               } else {
+                                                       panic!();
+                                               }
+                                       } else {
+                                               htlc_resolution.write(writer)?;
+                                       }
                                },
-                               &InboundHTLCState::AwaitingAnnouncedRemoteRevoke(ref htlc_state) => {
+                               &InboundHTLCState::AwaitingAnnouncedRemoteRevoke(ref htlc_resolution) => {
                                        2u8.write(writer)?;
-                                       htlc_state.write(writer)?;
+                                       if version_to_write <= 3 {
+                                               if let InboundHTLCResolution::Resolved { pending_htlc_status } = htlc_resolution {
+                                                       pending_htlc_status.write(writer)?;
+                                               } else {
+                                                       panic!();
+                                               }
+                                       } else {
+                                               htlc_resolution.write(writer)?;
+                                       }
                                },
                                &InboundHTLCState::Committed => {
                                        3u8.write(writer)?;
@@ -7680,6 +8684,11 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
 
                let holder_max_accepted_htlcs = if self.context.holder_max_accepted_htlcs == DEFAULT_MAX_HTLCS { None } else { Some(self.context.holder_max_accepted_htlcs) };
 
+               let mut monitor_pending_update_adds = None;
+               if !self.context.monitor_pending_update_adds.is_empty() {
+                       monitor_pending_update_adds = Some(&self.context.monitor_pending_update_adds);
+               }
+
                write_tlv_fields!(writer, {
                        (0, self.context.announcement_sigs, option),
                        // minimum_depth and counterparty_selected_channel_reserve_satoshis used to have a
@@ -7697,6 +8706,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        (7, self.context.shutdown_scriptpubkey, option),
                        (8, self.context.blocked_monitor_updates, optional_vec),
                        (9, self.context.target_closing_feerate_sats_per_kw, option),
+                       (10, monitor_pending_update_adds, option), // Added in 0.0.122
                        (11, self.context.monitor_pending_finalized_fulfills, required_vec),
                        (13, self.context.channel_creation_height, required),
                        (15, preimages, required_vec),
@@ -7715,6 +8725,8 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        (39, pending_outbound_blinding_points, optional_vec),
                        (41, holding_cell_blinding_points, optional_vec),
                        (43, malformed_htlcs, optional_vec), // Added in 0.0.119
+                       // 45 and 47 are reserved for async signing
+                       (49, self.context.local_initiated_shutdown, option), // Added in 0.0.122
                });
 
                Ok(())
@@ -7790,8 +8802,22 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                                cltv_expiry: Readable::read(reader)?,
                                payment_hash: Readable::read(reader)?,
                                state: match <u8 as Readable>::read(reader)? {
-                                       1 => InboundHTLCState::AwaitingRemoteRevokeToAnnounce(Readable::read(reader)?),
-                                       2 => InboundHTLCState::AwaitingAnnouncedRemoteRevoke(Readable::read(reader)?),
+                                       1 => {
+                                               let resolution = if ver <= 3 {
+                                                       InboundHTLCResolution::Resolved { pending_htlc_status: Readable::read(reader)? }
+                                               } else {
+                                                       Readable::read(reader)?
+                                               };
+                                               InboundHTLCState::AwaitingRemoteRevokeToAnnounce(resolution)
+                                       },
+                                       2 => {
+                                               let resolution = if ver <= 3 {
+                                                       InboundHTLCResolution::Resolved { pending_htlc_status: Readable::read(reader)? }
+                                               } else {
+                                                       Readable::read(reader)?
+                                               };
+                                               InboundHTLCState::AwaitingAnnouncedRemoteRevoke(resolution)
+                                       },
                                        3 => InboundHTLCState::Committed,
                                        4 => InboundHTLCState::LocalRemoved(Readable::read(reader)?),
                                        _ => return Err(DecodeError::InvalidValue),
@@ -7952,7 +8978,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                let channel_update_status = Readable::read(reader)?;
 
                #[cfg(any(test, fuzzing))]
-               let mut historical_inbound_htlc_fulfills = HashSet::new();
+               let mut historical_inbound_htlc_fulfills = new_hash_set();
                #[cfg(any(test, fuzzing))]
                {
                        let htlc_fulfills_len: u64 = Readable::read(reader)?;
@@ -8002,10 +9028,13 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
 
                let mut is_batch_funding: Option<()> = None;
 
+               let mut local_initiated_shutdown: Option<()> = None;
+
                let mut pending_outbound_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
                let mut holding_cell_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
 
                let mut malformed_htlcs: Option<Vec<(u64, u16, [u8; 32])>> = None;
+               let mut monitor_pending_update_adds: Option<Vec<msgs::UpdateAddHTLC>> = None;
 
                read_tlv_fields!(reader, {
                        (0, announcement_sigs, option),
@@ -8018,6 +9047,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        (7, shutdown_scriptpubkey, option),
                        (8, blocked_monitor_updates, optional_vec),
                        (9, target_closing_feerate_sats_per_kw, option),
+                       (10, monitor_pending_update_adds, option), // Added in 0.0.122
                        (11, monitor_pending_finalized_fulfills, optional_vec),
                        (13, channel_creation_height, option),
                        (15, preimages_opt, optional_vec),
@@ -8036,6 +9066,8 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        (39, pending_outbound_blinding_points_opt, optional_vec),
                        (41, holding_cell_blinding_points_opt, optional_vec),
                        (43, malformed_htlcs, optional_vec), // Added in 0.0.119
+                       // 45 and 47 are reserved for async signing
+                       (49, local_initiated_shutdown, option),
                });
 
                let (channel_keys_id, holder_signer) = if let Some(channel_keys_id) = channel_keys_id {
@@ -8188,6 +9220,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                                monitor_pending_forwards,
                                monitor_pending_failures,
                                monitor_pending_finalized_fulfills: monitor_pending_finalized_fulfills.unwrap(),
+                               monitor_pending_update_adds: monitor_pending_update_adds.unwrap_or(Vec::new()),
 
                                signer_pending_commitment_update: false,
                                signer_pending_funding: false,
@@ -8266,8 +9299,12 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                                channel_type: channel_type.unwrap(),
                                channel_keys_id,
 
+                               local_initiated_shutdown,
+
                                blocked_monitor_updates: blocked_monitor_updates.unwrap(),
-                       }
+                       },
+                       #[cfg(any(dual_funding, splicing))]
+                       dual_funding_channel_context: None,
                })
        }
 }
@@ -8313,6 +9350,18 @@ mod tests {
        use bitcoin::address::{WitnessProgram, WitnessVersion};
        use crate::prelude::*;
 
+       #[test]
+       fn test_channel_state_order() {
+               use crate::ln::channel::NegotiatingFundingFlags;
+               use crate::ln::channel::AwaitingChannelReadyFlags;
+               use crate::ln::channel::ChannelReadyFlags;
+
+               assert!(ChannelState::NegotiatingFunding(NegotiatingFundingFlags::new()) < ChannelState::FundingNegotiated);
+               assert!(ChannelState::FundingNegotiated < ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new()));
+               assert!(ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new()) < ChannelState::ChannelReady(ChannelReadyFlags::new()));
+               assert!(ChannelState::ChannelReady(ChannelReadyFlags::new()) < ChannelState::ShutdownComplete);
+       }
+
        struct TestFeeEstimator {
                fee_est: u32
        }
@@ -8417,7 +9466,7 @@ mod tests {
                // same as the old fee.
                fee_est.fee_est = 500;
                let open_channel_msg = node_a_chan.get_open_channel(ChainHash::using_genesis_block(network));
-               assert_eq!(open_channel_msg.feerate_per_kw, original_fee);
+               assert_eq!(open_channel_msg.common_fields.commitment_feerate_sat_per_1000_weight, original_fee);
        }
 
        #[test]
@@ -8448,7 +9497,7 @@ mod tests {
 
                // Node B --> Node A: accept channel, explicitly setting B's dust limit.
                let mut accept_channel_msg = node_b_chan.accept_inbound_channel();
-               accept_channel_msg.dust_limit_satoshis = 546;
+               accept_channel_msg.common_fields.dust_limit_satoshis = 546;
                node_a_chan.accept_channel(&accept_channel_msg, &config.channel_handshake_limits, &channelmanager::provided_init_features(&config)).unwrap();
                node_a_chan.context.holder_dust_limit_satoshis = 1560;
 
@@ -8766,7 +9815,7 @@ mod tests {
 
                // Node B --> Node A: accept channel, explicitly setting B's dust limit.
                let mut accept_channel_msg = node_b_chan.accept_inbound_channel();
-               accept_channel_msg.dust_limit_satoshis = 546;
+               accept_channel_msg.common_fields.dust_limit_satoshis = 546;
                node_a_chan.accept_channel(&accept_channel_msg, &config.channel_handshake_limits, &channelmanager::provided_init_features(&config)).unwrap();
                node_a_chan.context.holder_dust_limit_satoshis = 1560;
 
@@ -8820,17 +9869,34 @@ mod tests {
        fn blinding_point_skimmed_fee_malformed_ser() {
                // Ensure that channel blinding points, skimmed fees, and malformed HTLCs are (de)serialized
                // properly.
+               let logger = test_utils::TestLogger::new();
                let feeest = LowerBoundedFeeEstimator::new(&TestFeeEstimator{fee_est: 15000});
                let secp_ctx = Secp256k1::new();
                let seed = [42; 32];
                let network = Network::Testnet;
+               let best_block = BestBlock::from_network(network);
                let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
 
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let config = UserConfig::default();
                let features = channelmanager::provided_init_features(&config);
-               let outbound_chan = OutboundV1Channel::<&TestKeysInterface>::new(&feeest, &&keys_provider, &&keys_provider, node_b_node_id, &features, 10000000, 100000, 42, &config, 0, 42, None).unwrap();
-               let mut chan = Channel { context: outbound_chan.context };
+               let mut outbound_chan = OutboundV1Channel::<&TestKeysInterface>::new(
+                       &feeest, &&keys_provider, &&keys_provider, node_b_node_id, &features, 10000000, 100000, 42, &config, 0, 42, None
+               ).unwrap();
+               let inbound_chan = InboundV1Channel::<&TestKeysInterface>::new(
+                       &feeest, &&keys_provider, &&keys_provider, node_b_node_id, &channelmanager::provided_channel_type_features(&config),
+                       &features, &outbound_chan.get_open_channel(ChainHash::using_genesis_block(network)), 7, &config, 0, &&logger, false
+               ).unwrap();
+               outbound_chan.accept_channel(&inbound_chan.get_accept_channel_message(), &config.channel_handshake_limits, &features).unwrap();
+               let tx = Transaction { version: 1, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
+                       value: 10000000, script_pubkey: outbound_chan.context.get_funding_redeemscript(),
+               }]};
+               let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
+               let funding_created = outbound_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap().unwrap();
+               let mut chan = match inbound_chan.funding_created(&funding_created, best_block, &&keys_provider, &&logger) {
+                       Ok((chan, _, _)) => chan,
+                       Err((_, e)) => panic!("{}", e),
+               };
 
                let dummy_htlc_source = HTLCSource::OutboundRoute {
                        path: Path {
@@ -9722,7 +10788,7 @@ mod tests {
                channel_type_features.set_zero_conf_required();
 
                let mut open_channel_msg = node_a_chan.get_open_channel(ChainHash::using_genesis_block(network));
-               open_channel_msg.channel_type = Some(channel_type_features);
+               open_channel_msg.common_fields.channel_type = Some(channel_type_features);
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
                let res = InboundV1Channel::<&TestKeysInterface>::new(&feeest, &&keys_provider, &&keys_provider,
                        node_b_node_id, &channelmanager::provided_channel_type_features(&config),
@@ -9805,7 +10871,7 @@ mod tests {
 
                // Set `channel_type` to `None` to force the implicit feature negotiation.
                let mut open_channel_msg = channel_a.get_open_channel(ChainHash::using_genesis_block(network));
-               open_channel_msg.channel_type = None;
+               open_channel_msg.common_fields.channel_type = None;
 
                // Since A supports both `static_remote_key` and `option_anchors`, but B only accepts
                // `static_remote_key`, it will fail the channel.
@@ -9851,7 +10917,7 @@ mod tests {
                ).unwrap();
 
                let mut open_channel_msg = channel_a.get_open_channel(ChainHash::using_genesis_block(network));
-               open_channel_msg.channel_type = Some(simple_anchors_channel_type.clone());
+               open_channel_msg.common_fields.channel_type = Some(simple_anchors_channel_type.clone());
 
                let res = InboundV1Channel::<&TestKeysInterface>::new(
                        &fee_estimator, &&keys_provider, &&keys_provider, node_id_a,
@@ -9878,7 +10944,7 @@ mod tests {
                ).unwrap();
 
                let mut accept_channel_msg = channel_b.get_accept_channel_message();
-               accept_channel_msg.channel_type = Some(simple_anchors_channel_type.clone());
+               accept_channel_msg.common_fields.channel_type = Some(simple_anchors_channel_type.clone());
 
                let res = channel_a.accept_channel(
                        &accept_channel_msg, &config.channel_handshake_limits, &simple_anchors_init