During the 0.3 release cycle, and due to persistent outages and issues with
GitHub, primary development for `rust-lightning` moved to
https://git.rust-bitcoin.org/lightningdevkit/rust-lightning. Issues filed on the
original GitHub repository are mirrored and the git tree is synchronized to
GitHub regularly.

API Updates
===========
 * Splicing now supports RBFing pending splices and the splicing APIs have
   changed in order to support this (#4427, #4290, #4486, #4516, #4490, etc)
 * Splicing now supports splicing funds in and out in the same splice (#4261).
 * Async signing via the `[Ecdsa]ChannelSigner` interfaces is now supported on
   all methods which are expected to support async (#4197, #4355, #4579).
 * `UserConfig::manually_accept_inbound_channels` has been removed
   (it is now always `true`). As incoming channels are now expected to be
   examined in event handling, `ChannelHandshakeLimits::max_funding_satoshis`
   has been removed (#4354, #4318).
 * `ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx` now defaults to
   `true`. It is expected that the lightning network will continue to slowly
   deprecate pre-anchor channels (#4354).
 * Anchor channels can now require zero counterparty reserve balance with
   `ChannelManager::create_channel_to_trusted_peer_0reserve` and
   `ChannelManager::accept_inbound_channel_from_trusted_peer` (#4428).
 * `ChainMonitor::new` now takes a `deferred` which skips writing
   `ChannelMonitorUpdate`s until `ChainMonitor::flush`. The background processor
   calls this automatically after `ChannelManager` persistence. When enabled,
   this prevents force-closures due to stale `ChannelManager`s (#4351).
 * The `LSPS2ServiceHandler` now expects LDK's `ChannelClosed` events to be
   forwarded to the new `channel_closed` method (#4656).
 * Any HTLC can now be intercepted by setting
   `UserConfig::htlc_interception_flags` to the appropriate value (#4300, #4338)
 * `LSPS1` service support has been added (#4282).
 * Support for BOLT 12 `PayerProof`s has been added (#4297).
 * Log output has been updated to avoid including the peer, channel, and payment
   data which also appear in the structured `Record`. Please ensure you log the
   structured `Record` data along with the text itself (#4217, #4228).
 * BOLT 12 payments can now receive arbitrary `payment_metadata` similar to BOLT
   11. The `MessageRouter` or `Router` can insert data into the
   `payment_metadata` map. It can then be read from
   `PaymentPurpose::Bolt12OfferPayment::payment_context` (#4584).
 * `ChannelManager::pay_for_offer_from_human_readable_name` has been removed in
   favor of the standalone `bitcoin-payment-instructions` crate (#4539, #4543).
 * `PaginatedKVStore` was added, with `FilesystemStore` requiring migration to
   the added `FilesystemStoreV2` for pagination support (#4347).
 * Phantom nodes can now receive to BOLT 12 offers (#4335).
 * `Event::DiscardFunding` is now used to communicate inputs and outputs which
   were not included in a splice, rather than `SpliceNegotiationFailed` (#4388).
 * Many bounds have been converted to being directly on a `Trait`, rather than a
   `Deref<Target = Trait>`, with a blanket `impl Trait` for `Deref` (#4311).
 * `ProbabilisticScoringFeeParameters::default()` had its penalties 5x'd, better
   reflecting the price/performance tradeoff users want (#4811).
 * `pay_for_bolt11_invoice` now takes an `OptionalBolt11PaymentParams` offering
   both custom TLVs and to pay only part of an MPP payment (#4263, #4373).
 * Many types previously deserialized with `(BlockHash, X)` are now deserialized
   with `(BlockLocator, X)` (#4266, #4576).
 * `BroadcasterInterface::broadcast_transactions` now takes a
   `TransactionType` for additional context (#4353, #4393, #4570).
 * `lightning_net_tokio::tor_connect_outbound` was added (#4305).
 * `Event::PaymentForwarded` now contains a list of previous/next HTLCs, in
   preparation for future support for trampoline forwards (#4304, #4767, #4793).
 * `lightning-background-processor` now calls
   `ChainMonitor::archive_fully_resolved_channel_monitors` regularly (#4288).
 * `ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel`
   has been split into `[un]announced_channel_...` variants (#4529).
 * `UtxoLookup` now uses a `Notifier` to indicate completion, which ultimately
   completes `P2PGossipSync::validation_completion_future` (#4294, #4348).
 * The MSRV of `rust-lightning` has been bumped to rustc 1.75 (#4002).
 * Various async interfaces which previously used `Pin<Box<dyn Future<..>>>` now
   use `impl Future<..>` thanks to the MSRV update (#4175).
 * `BlindedPaymentPath` now supports adding dummy hops to obscure the recipient.
   While these are used by `DefaultRouter`, the privacy they provide is limited
   due to unique features of the dummy hops (#4152).
 * `DefaultMessageRouter` now examines the `MessageContext` to determine how
   aggressively to pad paths, making a space-privacy tradeoff (#4213).
 * `VerifiedInvoiceRequest` is now parameterized based on the key derivation
   strategy. Several APIs have changed as a result (#3964).
 * `InFlightHtlcs` now tracks blinded paths, avoiding path saturation (#4072).
 * `UpdateAddHTLC::accountable` was added and is now relayed for forwarded
   payments, see bLIP #4 (#4232).
 * `RecentPaymentDetails::is_probe` was added (#4603).
 * `RecentPaymentDetails::{pending_fee_msat,fee_paid_msat}` were added (#4674).
 * `ChannelDetails::splice_details` was added to list pending splices (#4687).
 * `ChannelDetails::next_splice_out_maximum_sat` was added (#4550).
 * `ChannelDetails::current_dust_exposure_msat` was added (#4470).
 * `Event::OnionMessageIntercepted::prev_hop` was added (#4682).
 * `LSPS2ServiceHandler::htlc_intercepted` now returns an `Err` if the SCID does
   not match an LSPS2 service SCID (#4160).

Backwards Compatibility
=======================
 * Payment metadata is now committed to in the payment secret. Thus, any
   existing BOLT 11 invoices issued with payment metadata will be invalidated
   on upgrade (and any newly issued invoices will be invalidated on downgrade).
   If this is problematic for you please open an issue (#4528, #4628).
 * Existing BOLT 12 refunds which have been issued but not yet claimed will not
   be claimable on 0.3 (#4685).
 * Outbound payments which are awaiting a BOLT 12 invoice response to our BOLT
   12 invoice request message will not be able to complete on 0.3 (#4213, #4685)
 * Receives over blinded payment paths are now authenticated with a
   `ReceiveAuthKey` similar to blinded message paths. In doing so, LDK 0.3+ will
   not accept payments over blinded paths created by prior versions. Note that
   this does *not* invalidate existing BOLT 12 offers (#4126).
 * A pending `Event::DiscardFunding` with `FundingInfo::Contribution` will be
   dropped on downgrade to 0.2 (#4919).
 * An LDK 0.2 `Event::SpliceFailed` is read by 0.3 as `SpliceNegotiationFailed`
   with `NegotiationFailureReason::Unknown` and no `contribution` (#4919).
 * HTLCs which were first received on an LDK version prior to LDK 0.2 will no
   longer be intercepted. Instead, they will be handled as if they were not
   intercepted and be forwarded/failed automatically (#4300).
 * Downgrading from LDK 0.3 while a splice is pending will fail when using
   async monitor updates (#4336).
 * Setting `OptionalBolt11PaymentParams::declared_total_mpp_value_msat_override`
   or `RecipientOnionFields::total_mpp_amount_msat` for a payment will break
   downgrade to 0.2 until the payment completes (#4373).
 * Downgrading below 0.3 with zero-reserve channels is not supported (#4428).
 * A pending splice negotiated before upgrading from a prior LDK version (e.g.
   0.2) cannot be RBF'd (#4687).
 * As RBF is not supported on prior LDK versions, downgrade after an RBF is not
   supported (#4427, #4687).
 * `ChannelSigner::get_per_commitment_point` must return `Ok(..)` for existing
   and previously revoked points during the first deserialization of a
   `ChannelManager` last written by LDK prior to 0.3.
   It may resume/begin async operation thereafter (#4197).
 * A `Route::route_params` of `None` is now deprecated and it will be required
   in a future version of LDK (#4704).

Performance Improvements
========================
 * `MonitorUpdatingPersisterAsync::read_all_channel_monitors_with_updates` now
   reads monitors and updates in parallel to speed up startup (#4147, #4921).
 * `lightning-block-sync::init::synchronize_listeners` has additional
   parallelism and caching (#4266).

Bug Fixes
=========
 * 0-conf channels which see a reorg immediately after their funding transaction
   confirms are no longer immediately closed (#4231).
 * Gossip about our channels is now forwarded to all peers even those who signal
   that we should not send them gossip. This fixes issues where an LDK node has
   multiple public channels but only one channel/path out to the broader network
   causing gossip about other channels to not propagate (#4216).
 * HTLCs which are added in a commitment in a `ChannelMonitorUpdate` that
   is only applied after the block containing the commitment transaction
   confirms are now properly failed. This should not impact users of a
  `ChainMonitor` which applies a `ChannelMonitorUpdate` immediately (#4434).
 * Stream write failures when serializing a `ChannelManager` no longer results
   in spurious `Event::SpliceNegotiationFailed`s and `Event::DiscardFunding`s
   for still-active splices (#4902).