lnd/docs/release-notes/release-notes-0.14.0.md

Release Notes

Networking & Tor

A new flag has been added to enable a hybrid tor connectivity mode, where tor is only used for onion address connections, and clearnet for everything else. This new behavior can be added using the tor.skip-proxy-for-clearnet-targets flag.

LN Peer-to-Peer Netowrk

Bitcoin Blockheaders in Ping Messages

In this release, we implement a long discussed mechanism to use the Lightning Network as a redundant block header source. By sending our latest block header with each ping message, we give peers another source (outside of the Bitcoin P2P network) they can use to spot check their chain state. Peers can also use this information to detect if they've been eclipsed from the traditional Bitcoin P2P network itself.

As is, we only send this data in Ping messages (which are periodically sent), in the future we could also move to send them as the partial payload for our pong messages, and also randomize the payload size requested as well.

The ListPeers RPC call will now also include a hex encoded version of the last ping message the peer has sent to us.

Backend Enhancements & Optimizations

Full remote database support

lnd now stores all its data in the same remote/external database such as etcd instead of only the channel state and wallet data. This makes lnd fully stateless and therefore makes switching over to a new leader instance almost instantaneous. Read the guide on leader election for more information.

Protocol Extensions

Explicit Channel Negotiation

[A new protocol extension has been added known as explicit channel negotiation] (https://github.com/lightningnetwork/lnd/pull/5669). This allows a channel initiator to signal their desired channel type to use with the remote peer. If the remote peer supports said channel type and agrees, the previous implicit negotiation based on the shared set of feature bits is bypassed, and the proposed channel type is used.

RPC Server

• Return payment address and add index from addholdinvoice call.

• The versions of several gRPC related libraries were bumped and the main rpc.proto was renamed to lightning.proto to fix a warning related to protobuf file name collisions.

• Stub code for interacting with lnrpc from a WASM context through JSON messages was added.

• LND now reports to systemd that RPC is ready (port bound, certificate generated, macaroons created, in case of wallet-unlock-password-file wallet unlocked). This can be used to avoid misleading error messages from dependent services if they use After systemd option.

Wallet

• It is now possible to fund a psbt without specifying any outputs. This option is useful for CPFP bumping of unconfirmed outputs or general utxo consolidation.

• The internal wallet can now also be created or restored by using an extended master root key (xprv) instead of an aezeed only. This allows wallet integrators to use existing seed mechanism that might already be in place. It is still not supported to use the same seed/root key on multiple lnd instances simultaneously though.

• Publish transaction is now reachable through lncli.

Security

Admin macaroon permissions

The default file permissions of admin.macaroon were changed from 0600 to 0640. This makes it easier to allow other users to manage LND. This is safe on common Unix systems because they always create a new group for each user.

If you use a strange system or changed group membership of the group running LND you may want to check your system to see if it introduces additional risk for you.

Safety

• Locally force closed channels are now kept in the channel.backup file until their time lock has fully matured.

Build System

• A new pre-submit check has been added to ensure that all PRs (aside from merge commits) add an entry in the release notes folder that at least links to PR being added.

• A new build target itest-race to help uncover undetected data races with our itests.

• The itest error whitelist check was removed to reduce the number of failed Travis builds.

• A flake in the Neutrino integration tests with anchor sweeps was addressed.

• The lnwire fuzz tests have been fixed and now run without crashing.

• A flake in the race unit tests was addressed that lead to failed tests sometimes when the CPU of the GitHub CI runner was strained too much.

Documentation

• Outdated warning about unsupported pruning was replaced with clarification that LND does support pruning

• Clarified 'ErrReservedValueInvalidated' error string to explain that the error is triggered by a transaction that would deplete funds already reserved for potential future anchor channel closings (via CPFP) and that more information (e.g., specific sat amounts) can be found in the debug logs.

Misc

• The direct use of certain syscalls in packages such as bbolt or lnd's own healthcheck package made it impossible to import lnd code as a library into projects that are compiled to WASM binaries. That problem was fixed by guarding those syscalls with build tags.

Code Health

Code cleanup, refactor, typo fixes

• Refactor the interaction between the htlcswitch and peer packages for cleaner separation.

• Unused error check removed.

• Shorten Pull Request check list by referring to the CI checks that are in place.

• Added minor fixes to contribution guidelines.

• Fixed typo in dest_custom_records description comment.

• Fixed payment test error message.

• Bumped version of github.com/miekg/dns library to fix a Dependabot alert.

• Fixed timeout flakes in async payment benchmark tests.

• Flake fix in async bidirectional payment test.

• Fixed context timeout when closing channels in tests.

• Fixed transaction not found in mempool flake in commitment deadline itest.

• Fixed a missing import and git tag in the healthcheck package.

• Fixed a data race in payment unit test.

• Missing dots in cmd interface.

• Link channel point logging

• Canceling the chain notifier no longer logs certain errors

• Fixed context leak in integration tests, and properly handled context timeout.

• Removed nested db tx

Database

• Ensure single writer for legacy code when using etcd backend.

• Optimized payment sequence generation to make LNDs payment throughput (and latency) with better when using etcd.

• More robust commit queue design to make it less likely that we retry etcd transactions and make the commit queue more scalable.

Performance improvements

• Update MC store in blocks to make payment throughput better when using etcd.

• The lnwire package now uses a write buffer pool when encoding/decoding messages. Such that most of the heap escapes are fixed, resulting in less memory being used when running lnd.

• [lnd will now no longer (in a steady state) need to open a new database transaction each time a private key needs to be derived for signing or ECDH operations]https://github.com/lightningnetwork/lnd/pull/5629). This results in a massive performance improvement across several routine operations at the

• [When decrypting incoming encrypted brontide messages on the wire, we'll now properly re-use the buffer that was allocated for the ciphertext to store the plaintext]https://github.com/lightningnetwork/lnd/pull/5622). When combined with the buffer pool, this ensures that we no longer need to allocate a new buffer each time we decrypt an incoming message, as we recycle these buffers in the peer.

Log system

• Save compressed log files from logrorate during itest.

Bug Fixes

A bug has been fixed that would cause lnd to try to bootstrap using the currnet DNS seeds when in SigNet mode.

A validation check for sane CltvLimit and FinalCltvDelta has been added for REST-initiated payments.

A bug has been fixed with Neutrino's RegisterConfirmationsNtfn and RegisterSpendNtfn calls that would cause notifications to be missed.

Documentation

The code contribution guidelines have been updated to mention the new requirements surrounding updating the release notes for each new change.

Contributors (Alphabetical Order)

• Andras Banki-Horvath
• de6df1re
• ErikEk
• Eugene Siegel
• Martin Habovstiak
• Oliver Gugger
• Wilmer Paulino
• xanoni
• Yong Yu
• Zero-1729