0.0.113 - Dec 16, 2022 - "Big Movement Intercepted"

API Updates

• ChannelManager::send_payment now takes an explicit PaymentId which is a loose idempotency token. See send_payment docs for more (#1761, #1826).
• HTLCs bound for SCIDs from ChannelManager::get_intercept_scid are now intercepted and can be forwarded manually over any channel (#1835, #1893).
• Confirm::get_relevant_txids now returns a BlockHash, expanding the set of cases where transaction_unconfirmed must be called, see docs (#1796).
• Pending outbound payments are no longer automatically timed-out a few blocks after failure. Thus, in order to avoid leaking memory, you MUST call ChannelManager::abandon_payment when you no longer wish to retry (#1761).
• ChannelManager::abandon_payment docs were updated to note that the payment may return to pending after a restart if no persistence occurs (#1907).
• Event::PaymentReceived has been renamed Event::PaymentClaimable (#1891).
• Event handling is now optionally async for Rust users (#1787).
• user_channel_id is now a u128 and random for inbound channels (#1790).
• A new ChannelReady event is generated whenever a channel becomes ready to be used, i.e., after both sides sent the channel_ready message (#1743).
• NetworkGraph now prunes channels where either node is offline for 2 weeks and refuses to accept re-announcements of pruned channels (#1735).
• Onion messages are now read in CustomOnionMessageHandler rather than via MaybeReadableArgs (#1809).
• Added a new util to generate an invoice with a custom hash (#1894) - create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash
• Signers are now by default re-derived using KeysInterface's new derive_channel_signer rather than read_chan_signer (#1867).
• Confirm::transactions_confirmed is now idempotent (#1861).
• ChannelManager::compute_inflight_htlcs has been added to fetch in-flight HTLCs for scoring. Note that InvoicePayer does this for you (#1830).
• Added PaymentClaimable::via_channel_id (#1856).
• Added the node_id (phantom or regular) to payment events (#1766).
• Added the funding transaction confirmations to ChannelDetails (#1856).
• BlindedRoute has been renamed BlindedPath (#1918).
• Support for the BOLT 4 "legacy" onion format has been removed, in line with its removal in the spec and vanishingly rare use (#1413).
• ChainMonitor::list_pending_monitor_updates was added (#1834).
• Signing for non-zero-fee anchor commitments is supported again (#1828).
• Several helpers for transaction matching and generation are now pub (#1839).

Bug Fixes

• Fixed a rare race where a crash may result in a pending HTLC not being failed backwards, leading to a force-closure by our counterparty (#1857).
• Avoid incorrectly assigning a lower-bound on channel liquidity when routing fails due to a closed channel earlier in the path (#1817).
• If a counterparty increases the channel fee, but not enough per our own fee estimator, we no longer force-close the channel (#1852).
• Several bugs in the lightning-background-processor future feature were fixed, including requirements doc corrections (#1843, #1845, #1851).
• Some failure messages sent back when failing an HTLC were corrected (#1895).
• rapid-gossip-sync no longer errors if an update is applied duplicatively or in rare cases when the graph is updated from payment failures (#1833).
• Sending onion messages to a blinded path in which we're the introduction node no longer fails (#1791).

Backwards Compatibility

• No ChannelReady events will be generated for previously existing channels, including those which become ready after upgrading to 0.0.113 (#1743).
• Once UserConfig::accept_intercept_htlcs is set, downgrades to LDK versions prior to 0.0.113 are not supported (#1835).
• Existing payments may see a PaymentClaimable::user_channel_id of 0 (#1856)
• When downgrading to a version of LDK prior to 0.0.113 when there are resolved payments waiting for a small timeout, the payments may not be removed, preventing payments with the same PaymentId (#1761).

In total, this release features 76 files changed, 11639 insertions, 6067 deletions in 210 commits from 18 authors, in alphabetical order:

• Antoine Riard
• Arik Sosman
• Devrandom
• Duncan Dean
• Elias Rohrer
• Gleb Naumenko
• Jeffrey Czyz
• John Cantrell
• Matt Corallo
• Tee8z
• Tobin C. Harding
• Tristan F
• Valentine Wallace
• Viktor Tigerström
• Wilmer Paulino
• benthecarman
• jurvis
• ssbright

0.0.112 - Oct 25, 2022 - "History Matters"

API Updates

• Result<(), ChannelMonitorUpdateErr> return values have been replaced with a ChannelMonitorUpdateStatus trinary enum. This better denotes that ChannelMonitorUpdateStatus::InProgress is not an error, but asynchronous persistence of a monitor update. Note that asynchronous persistence still has some edge cases and is not yet recommended for production (#1106).
• ChannelMonitor persistence failure no longer automatically broadcasts the latest commitment transaction. See the ChannelMonitorUpdateStatus::PermanentFailure docs for more info (#1106).
• *Features::known has been replaced with individual *MessageHandler::provided_*_features methods (#1707).
• OnionMessenger now takes a CustomOnionMessageHandler implementation, allowing you to send and receive custom onion messages (#1748).
• ProbabilisticScorer now tracks the historical distribution of liquidity estimates for channels. See new historical_* parameters in ProbabilisticScoringParameters for more details (#1625).
• lightning-block-sync's BlockSource trait now supports BIP 157/158 filtering clients by returning only header data for some blocks (#1706).
• lightning-invoice's Router trait now accepts an InFlightHtlcs to ensure we do not over-use a remote channel's funds during routing (#1694). Note that this was previously backported to 0.0.111 for bindings users.
• NetworkGraph::remove_stale_channels has been renamed NetworkGraph::remove_stale_channels_and_tracking as NetworkGraph now refuses to re-add nodes and channels that were recently removed (#1649).
• The lightning-rapid-gossip-sync crate now supports no-std (#1708).
• The default ProbabilisticScoringParameters::liquidity_offset_half_life has been increased to six hours from one (#1754).
• All commitment transaction building logic for anchor outputs now assumes the no-HTLC-tx-fee variant (#1685).
• A number of missing Eq implementations were added (#1763).

Bug Fixes

• lightning-background-processor now builds without error with the futures feature (#1744).
• ChannelManager::get_persistable_update_future's returned Future has been corrected to not fail to be awoken in some cases (#1758).
• Asynchronously performing the initial ChannelMonitor persistence is now safe (#1678).
• Redundantly applying rapid gossip sync updates no longer Errs (#1764).
• Nodes which inform us via payment failures that they should no longer be used are now removed from the network graph. Some LND nodes spuriously generate this error and may remove themselves from our graph (#1649).

In total, this release features 134 files changed, 6598 insertions, 4370 deletions in 109 commits from 13 authors, in alphabetical order:

• Duncan Dean
• Elias Rohrer
• Gabriel Comte
• Gursharan Singh
• Jeffrey Czyz
• Jurvis Tan
• Matt Corallo
• Max Fang
• Paul Miller
• Valentine Wallace
• Viktor Tigerström
• Wilmer Paulino
• acid-bit

"Saturated with Messages"

API Updates

• Support for relaying onion messages has been added via a new OnionMessenger struct when passed as the OnionMessageHandler to a PeerManager. Pre-encoded onion messages can also be sent and received (#1503, #1650, #1652, #1688).
• Rate-limiting of outbound gossip syncs has been rewritten to utilize less buffering inside LDK. The new rate-limiting is also used for onion messages to avoid delaying other messages (#1604. #1660, #1683).
• Rather than spawning a full OS thread, lightning-background-processor has a new process_events_async method which takes the place of a BackgroundProcessor for those using Rust's async (#1657).
• ChannelManager::get_persistable_update_future has been added to block on a ChannelManager needing re-persistence in a Rust async environment (#1657).
• The Filter::register_output return value has been removed, as it was very difficult to correctly implement (i.e., without blocking). Users previously using it should instead pass dependent transactions in via additional chain::Confirm::transactions_confirmed calls (#1663).
• ChannelHandshakeConfig::their_channel_reserve_proportional_millionths has been added to allow configuring counterparty reserve values (#1619).
• KeysInterface::ecdh has been added as an ECDH oracle (#1503, #1658).
• The rust-bitcoin dependency has been updated 0.29 (#1658).
• The bitcoin_hashes dependency has been updated 0.11 (#1677).
• ChannelManager::broadcast_node_announcement has been moved to PeerManager (#1699).
• channel_ and node_announcements are now rebroadcast automatically to all new peers which connect (#1699).
• {Init,Node}Features sent to peers/broadcasted are now fetched via the various *MessageHandler traits, rather than hard-coded (#1701, #1688).
• Event::PaymentPathFailed::rejected_by_dest has been renamed payment_failed_permanently (#1702).
• Invoice now derives the std Hash trait (#1575).
• {Signed,}RawInvoice::hash have been renamed signable_hash (#1714).
• chain::AccessError now derives the std Debug trait (#1709).
• ReadOnlyNetworkGraph::list_{channels,nodes} have been added largely for users of downstream bindings (#1651).
• ChannelMonitor::get_counterparty_node_id is now available (#1635).

Bug Fixes

• The script compared with that returned from chain::Access was incorrect ~half of the time, causing spurious gossip rejection (#1666).
• Pending in-flight HTLCs are now considered when calculating new routes, ensuring, e.g. MPP retries do not take known-saturated paths (#1643).
• Counterparty-revoked outputs are now included in get_claimable_balance output via a new Balance::CounterpartyRevokedOutputClaimable (#1495).
• Inbound HTLCs for which we do not (yet) have a preimage are now included in get_claimable_balance via a Balance::MaybePreimageClaimableHTLC (#1673).
• Probes that fail prior to being sent over their first hop are correctly failed with a Event::ProbeFailed rather than a PaymentPathFailed (#1704).
• Pending Event::HTLCHandlingFaileds are no longer lost on restart (#1700).
• HTLCs that fail prior to being sent over their first hop are now marked as retryable via !PaymentPathFailed::payment_failed_permanently (#1702).
• Dust HTLCs are now considered failed in the payment tracking logic after the commitment transaction confirms, allowing retry on restart (#1691).
• On machines with buggy "monotonic" clocks, LDK will no longer panic if time goes backwards (#1692).

Backwards Compatibility

• The new current_time argument to PeerManager constructors must be set to a UNIX timestamp for upgraded nodes; new nodes may use a counter (#1699).
• Balance::CounterpartyRevokedOutputClaimable will never be generated for channels that were observed to go on-chain with LDK versions prior to 0.0.111 (#1495).
• ChannelMonitor::get_counterparty_node_id will return None for all channels opened on a version of LDK prior to 0.0.110 (#1635).
• Setting their_channel_reserve_proportional_millionths to any value other than the default will cause LDK versions prior to 0.0.104 to be unable to read the serialized ChannelManager (#1619).

Security

0.0.111 fixes a denial-of-service vulnerability which is reachable from untrusted input in deployments accepting 0conf channels, or via a race-condition in deployments creating outbound 0conf channels.

• LDK versions prior to 0.0.111 may spuriously panic when receiving a block if they are awaiting the construction of a funding transaction for a 0-conf channel (#1711). 0-conf support was added in LDK version 0.0.107.

In total, this release features 84 files changed, 6306 insertions, 1960 deletions in 121 commits from 11 authors, in alphabetical order:

• Arik Sosman
• Devrandom
• Duncan Dean
• Elias Rohrer
• Gursharan Singh
• Matt Corallo
• NicolaLS
• Valentine Wallace
• Viktor Tigerström
• jurvis
• ok300

API Updates

• ChannelManager::send_probe and Score::probe_{failed,successful} have been added to make probing more explicit, as well as new Event::Probe{Failed,Successful} events (#1567).
• ProbabilisticScoringParameters::banned_nodes has been renamed manual_node_penalties and changed to take msat penalties (#1592).
• Per-payment tracking of failed paths was added to enable configuration of ProbabilisticScoringParameters::considered_impossible_penalty_msat (#1600)
• ProbabilisticScoringParameters::base_penalty_amount_multiplier_msat was added to allow a penalty that is only amount-dependent (#1617).
• ProbabilisticScoringParameters::amount_penalty_multiplier_msat was renamed liquidity_penalty_amount_multiplier_msat (#1617).
• A new Event::HTLCHandlingFailed has been added which provides visibility into failures to forward/claim accepted HTLCs (#1403).
• Support has been added for DNS hostnames in the NetAddress type, see BOLT PR #911 (#1553).
• GossipSync now has rapid, p2p, and none constructors (#1618).
• lightning-net-tokio no longer requires types to be in Arcs (#1623).
• The htlc_maximum_msat field is now required in ChannelUpdate gossip messages. In tests this rejects < 1% of channels (#1519).
• ReadOnlyNetworkGraph::{channel,node} have been added to query for individual channel/node data, primarily for bindings users (#1543).
• FeeEstimator implementations are now wrapped internally to ensure values below 253 sats/kW are never used (#1552).
• Route selection no longer attempts to randomize path selection. This is unlikely to lead to a material change in the paths selected (#1610).

Bug Fixes

• Fixed a panic when deserializing ChannelDetails objects (#1588).
• When routing, channels are no longer fully saturated before MPP splits are generated, instead a configuration knob was added as PaymentParameters::max_channel_saturation_power_of_half (#1605).
• Fixed a panic which occurred in ProbabilisticScorer when wallclock time goes backwards across a restart (#1603).

Serialization Compatibility

• All new fields are ignored by prior versions of LDK. All new fields are not present when reading objects serialized by prior versions of LDK.
• Channel information written in the NetworkGraph which is missing htlc_maximum_msat may be dropped on deserialization (#1519).
• Similarly, node information written in the NetworkGraph which contains an invalid hostname may be dropped on deserialization (#1519).

In total, this release features 79 files changed, 2935 insertions, 1363 deletions in 52 commits from 9 authors, in alphabetical order:

• Duncan Dean
• Elias Rohrer
• Jeffrey Czyz
• Matt Corallo
• Max Fang
• Viktor Tigerström
• Willem Van Lint
• Wilmer Paulino
• jurvis

API Updates

• ChannelManager::update_channel_config has been added to allow the fields in ChannelConfig to be changed in a given channel after open (#1527).
• If we reconnect to a peer which proves we have a stale channel state, rather than force-closing we will instead panic to provide an opportunity to switch to the latest state and continue operating without channel loss (#1564).
• A NodeAlias struct has been added which handles string sanitization for node aliases via the Display trait (#1544).
• ProbabilisticScoringParameters now has a banned_nodes set which we will never route through during path finding (#1550).
• ProbabilisticScoringParameters now offers an anti_probing_penalty_msat option to prefer channels which afford better privacy when routing (#1555).
• ProbabilisticScorer now provides access to its estimated liquidity range for a given channel via estimated_channel_liquidity_range (#1549).
• ChannelManager::force_close_channel has been renamed force_close_broadcasting_latest_txn and force_close_without_broadcasting_txn has been added (#1564).
• Options which cannot be changed at runtime have been moved from ChannelConfig to ChannelHandshakeConfig (#1529).
• find_route takes &NetworkGraph instead of `ReadOnlyNetworkGraph (#1583).
• ChannelDetails now contains a copy of the current ChannelConfig (#1527).
• The lightning-invoice crate now optionally depends on serde, with Invoice implementing serde::{Deserialize,Serialize} if enabled (#1548).
• Several fields in UserConfig have been renamed for clarity (#1540).

Bug Fixes

• find_route no longer selects routes with more than PaymentParameters::max_mpp_path_count paths, and ChannelManager::send_payment no longer refuses to send along routes with more than ten paths (#1526).
• Fixed two cases where HTLCs pending at the time a counterparty broadcasts a revoked commitment transaction are considered resolved prior to their actual resolution on-chain, possibly passing the update to another channel (#1486).
• HTLCs which are relayed through LDK may now have a total expiry time two weeks in the future, up from one, reducing forwarding failures (#1532).

Serialization Compatibility

• All new fields are ignored by prior versions of LDK. All new fields are not present when reading objects serialized by prior versions of LDK.
• ChannelConfig's serialization format has changed and is not compatible with any previous version of LDK. Attempts to read values written by a previous version of LDK will fail and attempts to read newly written objects using a previous version of LDK will fail. It is not expected that users are serializing ChannelConfig using the LDK serialization API, however, if a backward compatibility wrapper is required, please open an issue.

Security

0.0.109 fixes a denial-of-service vulnerability which is reachable from untrusted input in some application deployments.

• Third parties which are allowed to open channels with an LDK-based node may fund a channel with a bogus and maliciously-crafted transaction which, when spent, can cause a panic in the channel's corresponding ChannelMonitor. Such a channel is never usable as it cannot be funded with a funding transaction which matches the required output script, allowing the ChannelMonitor for such channels to be safely purged as a workaround on previous versions of LDK. Thanks to Eugene Siegel for reporting this issue.

In total, this release features 32 files changed, 1948 insertions, 532 deletions in 33 commits from 9 authors, in alphabetical order:

• Antoine Riard
• Daniel Granhão
• Elias Rohrer
• Jeffrey Czyz
• Matt Corallo
• Matt Faltyn
• NicolaLS
• Valentine Wallace
• Wilmer Paulino

Bug Fixes

• Fixed lightning-background-processor build in release mode.

In total, this release features 9 files changed, 120 insertions, 74 deletions in 5 commits from 4 authors, in alphabetical order:

• Elias Rohrer
• Matt Corallo
• Max Fang
• Viktor Tigerström

0.0.107

API Updates

• Channels larger than 16777215 sats (Wumbo!) are now supported and can be enabled for inbound channels using ChannelHandshakeLimits::max_funding_satoshis (#1425).
• Support for feature option_zeroconf, allowing immediate forwarding of payments after channel opening. This is configured for outbound channels using ChannelHandshakeLimits::trust_own_funding_0conf whereas ChannelManager::accept_inbound_channel_from_trusted_peer_0conf has to be used for accepting inbound channels (#1401, #1505).
• ChannelManager::claim_funds no longer returns a bool to indicate success. Instead, an Event::PaymentClaimed is generated if the claim was successful. Likewise, ChannelManager::fail_htlc_backwards no longer has a return value (#1434).
• lightning-rapid-gossip-sync is a new crate for syncing gossip data from a server, primarily aimed at mobile devices (#1155).
• RapidGossipSync can be passed to BackgroundProcessor in order to persist the NetworkGraph and handle NetworkUpdates during event handling (#1433, #1517).
• NetGraphMsgHandler has been renamed to P2PGossipSync, the network_graph module has been renamed to gossip, and NetworkUpdate::ChannelClosed has been renamed NetworkUpdate::ChannelFailure (#1159).
• Added a filtered_block_connected method to chain::Listen and a default implementation of block_connected for those fetching filtered instead of full blocks (#1453).
• The lightning-block-sync crate's BlockSource trait methods now take &self instead of &mut self (#1307).
• inbound_payment module is now public to allow for creating invoices without a ChannelManager (#1384).
• lightning-block-sync's init and poll modules support &dyn BlockSource which can be determined at runtime (#1423).
• lightning-invoice crate's utils now accept an expiration time (#1422, #1474).
• Event::PaymentForwarded includes prev_channel_id and next_channel_id (#1419, #1475).
• chain::Watch::release_pending_monitor_events' return type now associates MonitorEvents with funding OutPoints (#1475).
• lightning-background-processor crate's Persister trait has been moved to lightning crate's util::persist module, which now has a general KVStorePersister trait. Blanket implementations of Persister and chainmonitor::Persist are given for types implementing KVStorePersister. lightning-persister's FilesystemPersister implements KVStorePersister (#1417).
• ChannelDetails and ChannelCounterparty include fields for HTLC minimum and maximum values (#1378).
• Added a max_inbound_htlc_value_in_flight_percent_of_channel field to ChannelHandshakeConfig, capping the total value of outstanding inbound HTLCs for a channel (#1444).
• ProbabilisticScorer is parameterized by a Logger, which it uses to log channel liquidity updates or lack thereof (#1405).
• ChannelDetails has an outbound_htlc_limit_msat field, which should be used in routing instead of outbound_capacity_msat (#1435).
• ProbabilisticScorer's channel liquidities can be logged via debug_log_liquidity_stats (#1460).
• BackgroundProcessor now takes an optional WriteableScore which it will persist using the Persister trait's new persist_scorer method (#1416).
• Upgraded to bitcoin crate version 0.28.1 (#1389).
• ShutdownScript::new_witness_program now takes a WitnessVersion instead of a NonZeroU8 (#1389).
• Channels will no longer be automatically force closed when the counterparty is disconnected due to incompatibility (#1429).
• ChannelManager methods for funding, accepting, and closing channels now take a counterparty_node_id parameter, which has also been added as a field to Event::FundingGenerationReady (#1479, #1485).
• InvoicePayer::new now takes a Retry enum (replacing the RetryAttempts struct), which supports both attempt- and timeout-based retrying (#1418).
• Score::channel_penalty_msat takes a ChannelUsage struct, which contains the capacity as an EffectiveCapacity enum and any potential in-flight HTLC value, rather than a single u64. Used by ProbabilisticScorer for more accurate penalties (#1456).
• build_route_from_hops is a new function useful for constructing a Route given a specific list of public keys (#1491).
• FundingLocked message has been renamed ChannelReady, and related identifiers have been renamed accordingly (#1506).
• core2::io or std::io (depending on feature flags no-std or std) is exported as a lightning::io module (#1504).
• The deprecated Scorer has been removed in favor or ProbabilisticScorer (#1512).

Performance Improvements

• lightning-persister crate's FilesystemPersister is faster by 15x (#1404).
• Log gossip query messages at GOSSIP instead of TRACE to avoid overwhelming default logging (#1421).
• PeerManager supports processing messages from different peers in parallel, and this is taken advantage of in gossip processing (#1023).
• Greatly reduced per-channel and per-node memory usage due to upgrade of secp256k1 crate to 0.22.1 and bitcoin crate to 0.28.1
• Reduced per-peer memory usage in PeerManager (#1472).

Spec Compliance

• find_route now assumes variable-length onions by default for nodes where support for the feature is unknown (#1414).
• A warn message is now sent when receiving a channel_reestablish with an old commitment transaction number rather than immediately force-closing the channel (#1430).
• When a channel_update message is included in an onion error's failuremsg, its message type is now encoded. Reading such messages is also supported (#1465).

Bug Fixes

• Fixed a bug where crashing while persisting a ChannelMonitorUpdate for a part of a multi-path payment could cause loss of funds due to a partial payment claim on restart (#1434).
• BackgroundProcessor has been fixed to improve serialization reliability on slow systems which can avoid force-closes (#1436).
• gossip_timestamp_filter filters are now honored when sending gossip to peers (#1452).
• During a reorg, only force-close a channel if its funding transaction is unconfirmed rather than as it loses confirmations (#1461).
• Fixed a rare panic in lightning-net-tokio when fetching a peer's socket address after the connection has been closed caused by a race condition (#1449).
• find_route will no longer return routes that would cause onion construction to fail in some cases (#1476).
• ProbabilisticScorer uses more precision when approximating log10 (#1406).

Serialization Compatibility

• All above new events/fields are ignored by prior clients. All above new events/fields are not present when reading objects serialized by prior versions of the library.
• ChannelManager serialization is no longer compatible with versions prior to 0.0.99 (#1401).
• Channels with option_zeroconf feature enabled (not required for 0-conf channel use) will be unreadable by versions prior to 0.0.107 (#1401, #1505).

In total, this release features 96 files changed, 9304 insertions, 4503 deletions in 153 commits from 18 authors, in alphabetical order:

• Arik Sosman
• Devrandom
• Duncan Dean
• Elias Rohrer
• Jeffrey Czyz
• John Cantrell
• John Corser
• Jurvis Tan
• Justin Moon
• KaFai Choi
• Mateusz Faltyn
• Matt Corallo
• Valentine Wallace
• Viktor Tigerström
• Vincenzo Palazzo
• atalw
• dependabot[bot]
• shamardy

API Updates

• Minimum supported rust version (MSRV) is now 1.41.1 (#1310).
• Lightning feature option_scid_alias is now supported and may be negotiated when opening a channel with a peer. It can be configured via ChannelHandshakeConfig::negotiate_scid_privacy and is off by default but will be on by default in the future (#1351).
• OpenChannelRequest now has a channel_type field indicating the features the channel will operate with and should be used to filter channels with undesirable features (#1351). See the Serialization Compatibility section.
• ChannelManager supports sending and receiving short channel id aliases in the funding_locked message. These are used when forwarding payments and constructing invoice route hints for improved privacy. ChannelDetails has a inbound_scid_alias field and a get_inbound_payment_scid method to support the latter (#1311).
• DefaultRouter and find_route take an additional random seed to improve privacy by adding a random CLTV expiry offset to each path's final hop. This helps obscure the intended recipient from adversarial intermediate hops (#1286). The seed is also used to randomize candidate paths during route selection (#1359).
• The lightning-block-sync crate's init::synchronize_listeners method interface has been relaxed to support multithreaded environments (#1349).
• ChannelManager::create_inbound_payment_for_hash's documentation has been corrected to remove the one-year restriction on invoice_expiry_delta_secs, which is only applicable to the deprecated create_inbound_payment_legacy and create_inbound_payment_for_hash_legacy methods (#1341).
• Features mutator methods now take self by reference instead of by value (#1331).
• The CLTV of the last hop in a path is now included when comparing against RouteParameters::max_total_cltv_expiry_delta (#1358).
• Invoice creation functions in lightning-invoice crate's utils module include versions that accept a description hash instead of only a description (#1361).
• RoutingMessageHandler::sync_routing_table has been renamed peer_connected (#1368).
• MessageSendEvent::SendGossipTimestampFilter has been added to indicate that a gossip_timestamp_filter should be sent (#1368).
• PeerManager takes an optional NetAddress in new_outbound_connection and new_inbound_connection, which is used to report back the remote address to the connecting peer in the init message (#1326).
• ChannelManager::accept_inbound_channel now takes a user_channel_id, which is used in a similar manner as in outbound channels. (#1381).
• BackgroundProcessor now persists NetworkGraph on a timer and upon shutdown as part of a new Persister trait, which also includes ChannelManager persistence (#1376).
• ProbabilisticScoringParameters now has a base_penalty_msat option, which default to 500 msats. It is applied at each hop to help avoid longer paths (#1375).
• ProbabilisticScoringParameters::liquidity_penalty_multiplier_msat's default value is now 40,000 msats instead of 10,000 msats (#1375).
• The lightning crate has a grind_signatures feature used to produce signatures with low r-values for more predictable transaction weight. This feature is on by default (#1388).
• ProbabilisticScoringParameters now has a amount_penalty_multiplier_msat option, which is used to further penalize large amounts (#1399).
• PhantomRouteHints, FixedPenaltyScorer, and ScoringParameters now implement Clone (#1346).

Bug Fixes

• Fixed a compilation error in ProbabilisticScorer under --feature=no-std (#1347).
• Invoice creation functions in lightning-invoice crate's utils module filter invoice hints in order to limit the invoice size (#1325).
• Fixed a bug where a funding_locked message was delayed by a block if the funding transaction was confirmed while offline, depending on the ordering of Confirm::transactions_confirmed calls when brought back online (#1363).
• Fixed a bug in NetGraphMsgHandler where it didn't continue to receive gossip messages from peers after initial connection (#1368, #1382).
• ChannelManager::timer_tick_occurred will now timeout a received multi-path payment (MPP) after three ticks if not received in full instead of waiting until near the HTLC timeout block(#1353).
• Fixed an issue with find_route causing it to be overly aggressive in using MPP over channels to the same first hop (#1370).
• Reduced time spent processing channel_update messages by checking signatures after checking if no newer messages have already been processed (#1380).
• Fixed a few issues in find_route which caused preferring paths with a higher cost (#1398).
• Fixed an issue in ProbabilisticScorer where a channel with not enough liquidity could still be used when retrying a failed payment if it was on a path with an overall lower cost (#1399).

Serialization Compatibility

• Channels open with option_scid_alias negotiated will be incompatible with prior releases (#1351). This may occur in the following cases:
  • Outbound channels when ChannelHandshakeConfig::negotiate_scid_privacy is enabled.
  • Inbound channels when automatically accepted from an OpenChannel message with a channel_type that has ChannelTypeFeatures::supports_scid_privacy return true. See UserConfig::accept_inbound_channels.
  • Inbound channels when manually accepted from an OpenChannelRequest with a channel_type that has ChannelTypeFeatures::supports_scid_privacy return true. See UserConfig::manually_accept_inbound_channels.

In total, this release features 43 files changed, 4052 insertions, 1274 deletions in 75 commits from 11 authors, in alphabetical order:

• Devrandom
• Duncan Dean
• Elias Rohrer
• Jeffrey Czyz
• Jurvis Tan
• Luiz Parreira
• Matt Corallo
• Omar Shamardy
• Viktor Tigerström
• dependabot[bot]
• psycho-pirate

API Updates

• Phantom node payments are now supported, allowing receipt of a payment on any one of multiple nodes without any coordination across the nodes being required. See the new PhantomKeysManager's docs for more, as well as requirements on KeysInterface::get_inbound_payment_key_material and lightning_invoice::utils::create_phantom_invoice (#1199).
• In order to support phantom node payments, several KeysInterface methods now accept a Recipient parameter to select between the local node_id and a phantom-specific one.
• ProbabilisticScorer, a Score based on learning the current balances of channels in the network, was added. It attempts to better capture payment success probability than the existing Scorer, though may underperform on nodes with low payment volume. We welcome feedback on performance (#1227).
• Score::channel_penalty_msat now always takes the channel value, instead of an Option (#1227).
• UserConfig::manually_accept_inbound_channels was added which, when set, generates a new Event::OpenChannelRequest, which allows manual acceptance or rejection of incoming channels on a per-channel basis (#1281).
• Payee has been renamed to PaymentParameters (#1271).
• PaymentParameters now has a max_total_cltv_expiry_delta field. This defaults to 1008 and limits the maximum amount of time an HTLC can be pending before it will either fail or be claimed (#1234).
• The lightning-invoice crate now supports no-std environments. This required numerous API changes around timestamp handling and std+no-std versions of several methods that previously assumed knowledge of the time (#1223, #1230).
• lightning-invoice now supports parsing invoices with expiry times of more than one year. This required changing the semantics of ExpiryTime (#1273).
• The CounterpartyCommitmentSecrets is now public, allowing external uses of the BOLT 3 secret storage scheme (#1299).
• Several Sign methods now receive HTLC preimages as proof of state transition, see new documentation for more (#1251).
• KeysInterface::sign_invoice now provides the HRP and other invoice data separately to make it simpler for external signers to parse (#1272).
• Sign::sign_channel_announcement now returns both the node's signature and the per-channel signature. InMemorySigner now requires the node's secret key in order to implement this (#1179).
• ChannelManager deserialization will now fail if the KeysInterface used has a different node_id than the ChannelManager expects (#1250).
• A new ErrorAction variant was added to send warning messages (#1013).
• Several references to chain::Listen objects in lightning-block-sync no longer require a mutable reference (#1304).

Bug Fixes

• Fixed a regression introduced in 0.0.104 where ChannelManager's internal locks could have an order violation leading to a deadlock (#1238).
• Fixed cases where slow code (including user I/O) could cause us to disconnect peers with ping timeouts in BackgroundProcessor (#1269).
• Now persist the ChannelManager prior to BackgroundProcessor stopping, preventing race conditions where channels are closed on startup even with a clean shutdown. This requires that users stop network processing and disconnect peers prior to BackgroundProcessor shutdown (#1253).
• Fields in ChannelHandshakeLimits provided via the override_config to create_channel are now applied instead of the default config (#1292).
• Fixed the generation of documentation on docs.rs to include API surfaces which are hidden behind feature flags (#1303).
• Added the channel_type field to accept_channel messages we send, which may avoid some future compatibility issues with other nodes (#1314).
• Fixed a bug where, if a previous LDK run using lightning-persister crashed while persisting updated data, we may have failed to initialize (#1332).
• Fixed a rare bug where having both pending inbound and outbound HTLCs on a just-opened inbound channel could cause ChannelDetails::balance_msat to underflow and be reported as large, or cause panics in debug mode (#1268).
• Moved more instances of verbose gossip logging from the Trace level to the Gossip level (#1220).
• Delayed announcement_signatures until the channel has six confirmations, slightly improving propagation of channel announcements (#1179).
• Several fixes in script and transaction weight calculations when anchor outputs are enabled (#1229).

Serialization Compatibility

• Using ChannelManager data written by versions prior to 0.0.105 will result in preimages for HTLCs that were pending at startup to be missing in calls to KeysInterface methods (#1251).
• Any phantom invoice payments received on a node that is not upgraded to 0.0.105 will fail with an "unknown channel" error. Further, downgrading to 0.0.104 or before and then upgrading again will invalidate existing phantom SCIDs which may be included in invoices (#1199).

Security

0.0.105 fixes two denial-of-service vulnerabilities which may be reachable from untrusted input in certain application designs.

• Route calculation spuriously panics when a routing decision is made for a path where the second-to-last hop is a private channel, included due to a multi-hop route hint in an invoice.
• ChannelMonitor::get_claimable_balances spuriously panics in some scenarios when the LDK application's local commitment transaction is confirmed while HTLCs are still pending resolution.

In total, this release features 109 files changed, 7270 insertions, 2131 deletions in 108 commits from 15 authors, in alphabetical order:

• Conor Okus
• Devrandom
• Elias Rohrer
• Jeffrey Czyz
• Jurvis Tan
• Ken Sedgwick
• Matt Corallo
• Naveen
• Tibo-lg
• Valentine Wallace
• Viktor Tigerström
• dependabot[bot]
• hackerrdave
• naveen
• vss96

API Updates

• A PaymentFailed event is now provided to indicate a payment has failed fully. This event is generated either after ChannelManager::abandon_payment is called for a given payment, or the payment times out, and there are no further pending HTLCs for the payment. This event should be used to detect payment failure instead of PaymentPathFailed::all_paths_failed, unless no payment retries occur via ChannelManager::retry_payment (#1202).
• Payment secrets are now generated deterministically using material from the new KeysInterface::get_inbound_payment_key_material (#1177).
• A PaymentPathSuccessful event has been added to ease passing success info to a scorer, along with a Score::payment_path_successful method to accept such info (#1178, #1197).
• Score::channel_penalty_msat has additional arguments describing the channel's capacity and the HTLC amount being sent over the channel (#1166).
• A new log level Gossip has been added, which is used for verbose information generated during network graph sync. Enabling the max_level_trace feature or ignoring Gossip log entries reduces log growth during initial start up from many GiB to several MiB (#1145).
• The allow_wallclock_use feature has been removed in favor of only using the std and no-std features (#1212).
• NetworkGraph can now remove channels that we haven't heard updates for in two weeks with NetworkGraph::remove_stale_channels{,with_time}. The first is called automatically if a NetGraphMsgHandler is passed to BackgroundProcessor::start (#1212).
• InvoicePayer::pay_pubkey was added to enable sending "keysend" payments to supported recipients, using the InvoicePayer to handle retires (#1160).
• user_payment_id has been removed from PaymentPurpose, and ChannelManager::create_inbound_payment{,_for_hash} (#1180).
• Updated documentation for several ChannelManager functions to remove stale references to panics which no longer occur (#1201).
• The Score and LockableScore objects have moved into the routing::scoring module instead of being in the routing module (#1166).
• The Time parameter to ScorerWithTime is no longer longer exposed, instead being fixed based on the std/no-std feature (#1184).
• ChannelDetails::balance_msat was added to fetch a channel's balance without subtracting the reserve values, lining up with on-chain claim amounts less on-chain fees (#1203).
• An explicit UserConfig::accept_inbound_channels flag is now provided, removing the need to set min_funding_satoshis to > 21 million BTC (#1173).
• Inbound channels that fail to see the funding transaction confirm within 2016 blocks are automatically force-closed with ClosureReason::FundingTimedOut (#1083).
• We now accept a channel_reserve value of 0 from counterparties, as it is insecure for our counterparty but not us (#1163).
• NetAddress::OnionV2 parsing was removed as version 2 onion services are no longer supported in modern Tor (#1204).
• Generation and signing of anchor outputs is now supported in the KeysInterface, though no support for them exists in the channel itself (#1176)

Bug Fixes

• Fixed a race condition in InvoicePayer where paths may be retried after the retry count has been exceeded. In this case the Event::PaymentPathFailed::all_paths_failed field is not a reliable payment failure indicator. There was no acceptable alternative indicator, Event::PaymentFailed as been added to provide one (#1202).
• Reduced the blocks-before-timeout we expect of outgoing HTLCs before refusing to forward. This check was overly strict and resulted in refusing to forward som HTLCs to a next hop that had a lower security threshold than us (#1119).
• LDK no longer attempt to update the channel fee for outbound channels when we cannot afford the new fee. This could have caused force-closure by our channel counterparty (#1054).
• Fixed several bugs which may have prevented the reliable broadcast of our own channel announcements and updates (#1169).
• Fixed a rare bug which may have resulted in spurious route finding failures when using last-hop hints and MPP with large value payments (#1168).
• KeysManager::spend_spendable_outputs no longer adds a change output that is below the dust threshold for non-standard change scripts (#1131).
• Fixed a minor memory leak when attempting to send a payment that fails due to an error when updating the ChannelMonitor (#1143).
• Fixed a bug where a FeeEstimator that returns values rounded to the next sat/vbyte may result in force-closures (#1208).
• Handle MPP timeout HTLC error codes, instead of considering the recipient to have sent an invalid error, removing them from the network graph (#1148)

Serialization Compatibility

• All above new events/fields are ignored by prior clients. All above new events/fields are not present when reading objects serialized by prior versions of the library.
• Payment secrets are now generated deterministically. This reduces the memory footprint for inbound payments, however, newly-generated inbound payments using ChannelManager::create_inbound_payment{,_for_hash} will not be receivable using versions prior to 0.0.104. ChannelManager::create_inbound_payment{,_for_hash}_legacy are provided for backwards compatibility (#1177).
• PaymentPurpose::InvoicePayment::user_payment_id will be 0 when reading objects written with 0.0.104 when read by 0.0.103 and previous (#1180).

In total, this release features 51 files changed, 5356 insertions, 2238 deletions in 107 commits from 9 authors, in alphabetical order:

• Antoine Riard
• Conor Okus
• Devrandom
• Duncan Dean
• Elias Rohrer
• Jeffrey Czyz
• Ken Sedgwick
• Matt Corallo
• Valentine Wallace

API Updates

• This release is almost entirely focused on a new API in the lightning-invoice crate - the InvoicePayer. InvoicePayer is a struct which takes a reference to a ChannelManager and a Router and retries payments as paths fail. It limits retries to a configurable number, but is not serialized to disk and may retry additional times across a serialization/load. In order to learn about failed payments, it must receive Events directly from the ChannelManager, wrapping a user-provided EventHandler which it provides all unhandled events to (#1059).
• get_route has been renamed find_route (#1059) and now takes a RouteParameters struct in replacement of a number of its long list of arguments (#1134). The Payee in the RouteParameters is stored in the Route object returned and provided in the RouteParameters contained in Event::PaymentPathFailed (#1059).
• ChannelMonitors must now be persisted after calls that provide new block data, prior to MonitorEvents being passed back to ChannelManager for processing. If you are using a ChainMonitor this is handled for you. The Persist API has been updated to Optionally take the ChannelMonitorUpdate as persistence events that result from chain data no longer have a corresponding update (#1108).
• routing::Score now has a payment_path_failed method which it can use to learn which channels often fail payments. It is automatically called by InvoicePayer for failed payment paths (#1144).
• The default Scorer implementation is now a type alias to a type generic across different clocks and supports serialization to persist scoring data across restarts (#1146).
• Event::PaymentSent now includes the full fee which was spent across all payment paths which were fulfilled or pending when the payment was fulfilled (#1142).
• Event::PaymentSent and Event::PaymentPathFailed now include the PaymentId which matches the PaymentId returned from ChannelManager::send_payment or InvoicePayer::pay_invoice (#1059).
• NetGraphMsgHandler now takes a Deref to the NetworkGraph, allowing for shared references to the graph data to make serialization and references to the graph data in the InvoicePayer's Router simpler (#1149).
• routing::Score::channel_penalty_msat has been updated to provide the NodeId of both the source and destination nodes of a channel (#1133).

Bug Fixes

• Previous versions would often disconnect peers during initial graph sync due to ping timeouts while processing large numbers of gossip messages. We now delay disconnecting peers if we receive messages from them even if it takes a while to receive a pong from them. Further, we avoid sending too many gossip messages between pings to ensure we should always receive pongs in a timely manner (#1137).
• If a payment was sent, creating an outbound HTLC and sending it to our counterparty (implying the ChannelMonitor was persisted on disk), but the ChannelManager was not persisted prior to shutdown/crash, no Event::PaymentPathFailed event was generated if the HTLC was eventually failed on chain. Events are now consistent irrespective of ChannelManager persistence or non-persistence (#1104).

Serialization Compatibility

• All above new Events/fields are ignored by prior clients. All above new Events/fields are not present when reading objects serialized by prior versions of the library.
• Payments for which a Route was generated using a previous version or for which the payment was originally sent by a previous version of the library will not be retried by an InvoicePayer.

This release was singularly focused and some contributions by third parties were delayed. In total, this release features 38 files changed, 4414 insertions, and 969 deletions in 71 commits from 2 authors, in alphabetical order:

• Jeffrey Czyz
• Matt Corallo

API Updates

• get_route now takes a Score as an argument. Score is queried during the route-finding process, returning the absolute amounts which you are willing to pay to avoid routing over a given channel. As a default, a Scorer is provided which returns a constant amount, with a suggested default of 500 msat. This translates to a willingness to pay up to 500 msat in additional fees per hop in order to avoid additional hops (#1124).
• Event::PaymentPathFailed now contains a short_channel_id field which may be filled in with a channel that can be "blamed" for the payment failure. Payment retries should likely avoid the given channel for some time (#1077).
• PublicKeys in NetworkGraph have been replaced with a NodeId struct which contains only a simple [u8; 33], substantially improving NetworkGraph deserialization performance (#1107).
• ChainMonitor's HashMap of ChannelMonitors is now private, exposed via Chainmonitor::get_monitor and ChainMonitor::list_monitors instead (#1112).
• When an outbound channel is closed prior to the broadcasting of its funding transaction, but after you call ChannelManager::funding_transaction_generated, a new event type, Event::DiscardFunding, is generated, informing you the transaction was not broadcasted and that you can spend the same inputs again elsewhere (#1098).
• ChannelManager::create_channel now returns the temporary channel ID which may later appear in Event::ChannelClosed or ChannelDetails prior to the channel being funded (#1121).
• Event::PaymentSent now contains the payment hash as well as the payment preimage (#1062).
• ReadOnlyNetworkGraph::get_addresses now returns owned NetAddress rather than references. As a side-effect this method is now exposed in foreign language bindings (#1115).
• The Persist and ChannelMonitorUpdateErr types have moved to the lightning::chain::chainmonitor and lightning::chain modules, respectively (#1112).
• ChannelManager::send_payment now returns a PaymentId which identifies a payment (whether MPP or not) and can be used to retry the full payment or MPP parts through retry_payment (#1096). Note that doing so is currently not crash safe, and you may find yourself sending twice. It is recommended that you not use the retry_payment API until the next release.

Bug Fixes

• Due to an earlier fix for the Lightning dust inflation vulnerability tracked in CVE-2021-41591/CVE-2021-41592/CVE-2021-41593 in 0.0.100, we required counterparties to accept a dust limit slightly lower than the dust limit now required by other implementations. This appeared as, at least, latest lnd always refusing to accept channels opened by LDK clients (#1065).
• If there are multiple channels available to the same counterparty, get_route would only consider the channel listed last as available for sending (#1100).
• Persist implementations returning ChannelMonitorUpdateErr::TemporaryFailure from watch_channel previously resulted in the ChannelMonitor not being stored at all, resulting in a panic after monitor updating is complete (#1112).
• If payments are pending awaiting forwarding at startup, an Event::PendingHTLCsForwardable event will always be provided. This ensures user code calls ChannelManager::process_pending_htlc_fowards even if it shut down while awaiting the batching timer during the previous run (#1076).
• If a call to ChannelManager::send_payment failed due to lack of availability of funds locally, LDK would store the payment as pending forever, with no ability to retry or fail it, leaking memory (#1109).

Serialization Compatibility

• All above new Events/fields are ignored by prior clients. All above new Events/fields, except for Event::PaymentSent::payment_hash are not present when reading objects serialized by prior versions of the library.

In total, this release features 32 files changed, 2248 insertions, and 1483 deletions in 51 commits from 7 authors, in alphabetical order:

• 1nF0rmed
• Duncan Dean
• Elias Rohrer
• Galder Zamarreño
• Jeffrey Czyz
• Matt Corallo
• Valentine Wallace

API Updates

• Custom message types are now supported directly in the PeerManager, allowing you to send and receive messages of any type that is not natively understood by LDK. This requires a new type bound on PeerManager, a CustomMessageHandler. IgnoringMessageHandler provides a simple default for this new bound for ignoring unknown messages (#1031, #1074).
• Route graph updates as a result of failed payments are no longer provided as MessageSendEvent::PaymentFailureNetworkUpdate but instead included in a new field in the Event::PaymentFailed events. Generally, this means route graph updates are no longer handled as a part of the PeerManager but instead through the new EventHandler implementation for NetGraphMsgHandler. To make this easy, a new parameter to lightning-background-processor::BackgroundProcessor::start is added, which contains an Optional NetGraphmsgHandler. If provided as Some, relevant events will be processed by the NetGraphMsgHandler prior to normal event handling (#1043).
• NetworkGraph is now, itself, thread-safe. Accordingly, most functions now take &self instead of &mut self and the graph data can be accessed through NetworkGraph.read_only (#1043).
• The balances available on-chain to claim after a channel has been closed are now exposed via ChannelMonitor::get_claimable_balances and ChainMonitor::get_claimable_balances. The second can be used to get information about all closed channels which still have on-chain balances associated with them. See enum variants of ln::channelmonitor::Balance and method documentation for the above methods for more information on the types of balances exposed (#1034).
• When one HTLC of a multi-path payment fails, the new field all_paths_failed in Event::PaymentFailed is set to false. This implies that the payment has not failed, but only one part. Payment resolution is only indicated by an Event::PaymentSent event or an Event::PaymentFailed with all_paths_failed set to true, which is also set for the last remaining part of a multi-path payment (#1053).
• To better capture the context described above, Event::PaymentFailed has been renamed to Event::PaymentPathFailed (#1084).
• A new event, ChannelClosed, is provided by ChannelManager when a channel is closed, including a reason and error message (if relevant, #997).
• lightning-invoice now considers invoices with sub-millisatoshi precision to be invalid, and requires millisatoshi values during construction (thus you must call amount_milli_satoshis instead of amount_pico_btc, #1057).
• The BaseSign interface now includes two new hooks which provide additional information about commitment transaction signatures and revocation secrets provided by our counterparty, allowing additional verification (#1039).
• The BaseSign interface now includes additional information for cooperative close transactions, making it easier for a signer to verify requests (#1064).
• Route has two additional helper methods to get fees and amounts (#1063).
• Txid and Transaction objects can now be deserialized from responses when using the HTTP client in the lightning-block-sync crate (#1037, #1061).

Bug Fixes

• Fix a panic when reading a lightning invoice with a non-recoverable signature. Further, restrict lightning invoice parsing to require payment secrets and better handle a few edge cases as required by BOLT 11 (#1057).
• Fix a panic when receiving multiple messages (such as HTLC fulfill messages) after a call to chain::Watch::update_channel returned Err(ChannelMonitorUpdateErr::TemporaryFailure) with no ChannelManager::channel_monitor_updated call in between (#1066).
• For multi-path payments, Event::PaymentSent is no longer generated multiple times, once for each independent part (#1053).
• Multi-hop route hints in invoices are now considered in the default router provided via get_route (#1040).
• The time peers have to respond to pings has been increased when building with debug assertions enabled. This avoids peer disconnections on slow hosts when running in debug mode (#1051).
• The timeout for the first byte of a response for requests from the lightning-block-sync crate has been increased to 300 seconds to better handle the long hangs in Bitcoin Core when it syncs to disk (#1090).

Serialization Compatibility

• Due to a bug in 0.0.100, Events written by 0.0.101 which are of a type not understood by 0.0.100 may lead to Err(DecodeError::InvalidValue) or corrupt deserialized objects in 0.100. Such Events will lead to an Err(DecodeError::InvalidValue) in versions prior to 0.0.100. The only such new event written by 0.0.101 is Event::ChannelClosed (#1087).
• Payments that were initiated in versions prior to 0.0.101 may still generate duplicate PaymentSent Events or may have spurious values for Event::PaymentPathFailed::all_paths_failed (#1053).
• The return values of ChannelMonitor::get_claimable_balances (and, thus, ChainMonitor::get_claimable_balances) may be spurious for channels where the spend of the funding transaction appeared on chain while running a version prior to 0.0.101. Balance information should only be relied upon for channels that were closed while running 0.0.101+ (#1034).
• Payments failed while running versions prior to 0.0.101 will never have a Some for the network_update field (#1043).

In total, this release features 67 files changed, 4980 insertions, 1888 deletions in 89 commits from 12 authors, in alphabetical order:

• Antoine Riard
• Devrandom
• Galder Zamarreño
• Giles Cope
• Jeffrey Czyz
• Joseph Goulden
• Matt Corallo
• Sergi Delgado Segura
• Tibo-lg
• Valentine Wallace
• abhik-99
• vss96

API Updates

• The lightning crate can now be built in no_std mode, making it easy to target embedded hardware for rust users. Note that mutexes are replaced with no-ops for such builds (#1008, #1028).
• LDK now supports sending and receiving "keysend" payments. This includes modifications to lightning::util::events::Event::PaymentReceived to indicate the type of payment (#967).
• A new variant, lightning::util::events::Event::PaymentForwarded has been added which indicates a forwarded payment has been successfully claimed and we've received a forwarding fee (#1004).
• lightning::chain::keysinterface::KeysInterface::get_shutdown_pubkey has been renamed to get_shutdown_scriptpubkey, returns a script, and is now called on channel open only if lightning::util::config::ChannelConfig::commit_upfront_shutdown_pubkey is set (#1019).
• Closing-signed negotiation is now more configurable, with an explicit lightning::util::config::ChannelConfig::force_close_avoidance_max_fee_satoshis field allowing you to select the maximum amount you are willing to pay to avoid a force-closure. Further, we are now less restrictive on the fee placed on the closing transaction when we are not the party paying it. To control the feerate paid on a channel at close-time, use ChannelManager::close_channel_with_target_feerate instead of close_channel (#1011).
• lightning_background_processor::BackgroundProcessor now stops the background thread when dropped (#1007). It is marked #[must_use] so that Rust users will receive a compile-time warning when it is immediately dropped after construction (#1029).
• Total potential funds burn on force-close due to dust outputs is now limited to lightning::util::config::ChannelConfig::max_dust_htlc_exposure_msat per channel (#1009).
• The interval on which lightning::ln::peer_handler::PeerManager::timer_tick_occurred should be called has been reduced to once every five seconds (#1035) and lightning::ln::channelmanager::ChannelManager::timer_tick_occurred should now be called on startup in addition to once per minute (#985).
• The rust-bitcoin and bech32 dependencies have been updated to their respective latest versions (0.27 and 0.8, #1012).

Bug Fixes

• Fix panic when reading invoices generated by some versions of c-lightning (#1002 and #1003).
• Fix panic when attempting to validate a signed message of incorrect length (#1010).
• Do not ignore the route hints in invoices when the invoice is over 250k sats (#986).
• Fees are automatically updated on outbound channels to ensure commitment transactions are always broadcastable (#985).
• Fixes a rare case where a lightning::util::events::Event::SpendableOutputs event is not generated after a counterparty commitment transaction is confirmed in a reorg when a conflicting local commitment transaction is removed in the same reorg (#1022).
• Fixes a remotely-triggerable force-closure of an origin channel after an HTLC was forwarded over a next-hop channel and the next-hop channel was force-closed by our counterparty (#1025).
• Fixes a rare force-closure case when sending a payment as a channel fundee when overdrawing our remaining balance. Instead the send will fail (#998).
• Fixes a rare force-closure case when a payment was claimed prior to a peer disconnection or restart, and later failed (#977).

Serialization Compatibility

• Pending inbound keysend payments which have neither been failed nor claimed when serialized will result in a ChannelManager which is not readable on pre-0.0.100 clients (#967).
• Because lightning::chain::keysinterface::KeysInterface::get_shutdown_scriptpubkey has been updated to return a script instead of only a PublicKey, ChannelManagers constructed with custom KeysInterface implementations on 0.0.100 and later versions will not be readable on previous versions. ChannelManagers created with 0.0.99 and prior versions will remain readable even after the a serialization roundtrip on 0.0.100, as long as no new channels are opened. Further, users using a lightning::chain::keysinterface::KeysManager as their KeysInterface will have ChannelManagers which are readable on prior versions as well (#1019).
• ChannelMonitorUpdates created by 0.0.100 and later for channels when lightning::util::config::ChannelConfig::commit_upfront_shutdown_pubkey is not set may not be readable by versions prior to 0.0.100 (#1019).
• HTLCs which were in the process of being claimed on-chain when a pre-0.0.100 ChannelMonitor was serialized may generate PaymentForwarded events with spurious fee_earned_msat values. This only applies to payments which were unresolved at the time of the upgrade (#1004).
• 0.0.100 clients with pending Event::PaymentForwarded events at serialization-time will generate serialized ChannelManager objects which 0.0.99 and earlier clients cannot read. The likelihood of this can be reduced by ensuring you process all pending events immediately before serialization (as is done by the lightning-background-processor crate, #1004).

In total, this release features 59 files changed, 5861 insertions, and 2082 deletions in 95 commits from 6 authors.

API Updates

• lightning_block_sync::poll::Validate is now public, allowing you to implement the lightning_block_sync::poll::Poll trait without lightning_block_sync::poll::ChainPoller (#956).
• lightning::ln::peer_handler::PeerManager no longer requires that no calls are made to referencing the same SocketDescriptor after disconnect_socket returns. This makes the API significantly less deadlock-prone and simplifies SocketDescriptor implementations significantly. The relevant changes have been made to lightning_net_tokio and PeerManager documentation has been substantially rewritten (#957).
• lightning::util::message_signing's sign and verify methods now take secret and public keys by reference instead of value (#974).
• Substantially more information is now exposed about channels in ChannelDetails. See documentation for more info (#984 and #988).
• The latest best block seen is now exposed in ChannelManager::current_best_block and ChannelMonitor::current_best_block (#984).
• Feerates charged when forwarding payments over channels is now set in ChannelConfig::fee_base_msat when the channel is opened. For existing channels, the value is set to the value provided in ChannelManagerReadArgs::default_config::channel_options the first time the ChannelManager is loaded in 0.0.99 (#975).
• We now reject HTLCs which are received to be forwarded over private channels unless UserConfig::accept_forwards_to_priv_channels is set. Note that UserConfig is never serialized and must be provided via ChannelManagerReadArgs::default_config at each start (#975).

Bug Fixes

• We now forward gossip messages to peers instead of only relaying locally-generated gossip or sending gossip messages during initial sync (#948).
• Correctly send channel_update messages to direct peers on private channels (#949). Without this, a private node connected to an LDK node over a private channel cannot receive funds as it does not know which fees the LDK node will charge.
• lightning::ln::channelmanager::ChannelManager no longer expects to be persisted spuriously after we receive a channel_update message about any channel in the routing gossip (#972).
• Asynchronous ChannelMonitor updates (using the ChannelMonitorUpdateErr::TemporaryFailure return variant) no longer cause spurious HTLC forwarding failures (#954).
• Transaction provided via ChannelMonitor::transactions_confirmed after ChannelMonitor::best_block_updated was called for a much later block now trigger all relevant actions as of the later block. Previously some transaction broadcasts or other responses required an additional block be provided via ChannelMonitor::best_block_updated (#970).
• We no longer panic in rare cases when an invoice contained last-hop route hints which were unusable (#958).

Node Compatibility

• We now accept spurious funding_locked messages sent prior to channel_reestablish messages after reconnect. This is a known, long-standing bug in lnd (#966).
• We now set the first_blocknum and number_of_blocks fields in reply_channel_range messages to values which c-lightning versions prior to 0.10 accepted. This avoids spurious force-closes from such nodes (#961).

Serialization Compatibility

• Due to a bug discovered in 0.0.98, if a ChannelManager is serialized on version 0.0.98 while an Event::PaymentSent is pending processing, the ChannelManager will fail to deserialize both on version 0.0.98 and later versions. If you have such a ChannelManager available, a simple patch will allow it to deserialize. Please file an issue if you need assistance (#973).

0.0.98 should be considered a release candidate to the first alpha release of Rust-Lightning and the broader LDK. It represents several years of work designing and fine-tuning a flexible API for integrating lightning into any application. LDK should make it easy to build a lightning node or client which meets specific requirements that other lightning node software cannot. As lightning continues to evolve, and new use-cases for lightning develop, the API of LDK will continue to change and expand. However, starting with version 0.1, objects serialized with prior versions will be readable with the latest LDK. While Rust-Lightning is approaching the 0.1 milestone, language bindings components of LDK available at https://github.com/lightningdevkit are still of varying quality. Some are also approaching an 0.1 release, while others are still much more experimental. Please note that, at 0.0.98, using Rust-Lightning on mainnet is strongly discouraged.

• Large API overhauls to make several major API surfaces much easier to work.
• C/C++ Bindings are a part of this release, however are still considered beta status. They are expected to mature as more language-specific binding work is built on top.