# 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.

## Backend Enhancements & Optimizations

### Full remote database support

`lnd` now stores [all its data in the same remote/external
database](https://github.com/lightningnetwork/lnd/pull/5484) 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](https://github.com/lightningnetwork/lnd/blob/master/docs/leader_election.md)
for more information.

## RPC Server

* [Return payment address and add index from
  addholdinvoice call](https://github.com/lightningnetwork/lnd/pull/5533).

* [The versions of several gRPC related libraries were bumped and the main
  `rpc.proto` was renamed to
  `lightning.proto`](https://github.com/lightningnetwork/lnd/pull/5473) 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](https://github.com/lightningnetwork/lnd/pull/5601).

* LND now [reports to systemd](https://github.com/lightningnetwork/lnd/pull/5536)
  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](https://github.com/lightningnetwork/lnd/pull/5442). 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`](https://github.com/lightningnetwork/lnd/pull/4717) 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](https://github.com/lightningnetwork/lnd/pull/5460).

## Security 

### Admin macaroon permissions

The default file permissions of admin.macaroon were [changed from 0600 to
0640](https://github.com/lightningnetwork/lnd/pull/5534). 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](https://github.com/lightningnetwork/lnd/pull/5528).

## Build System

* [A new pre-submit check has been
  added](https://github.com/lightningnetwork/lnd/pull/5520) to ensure that all
  PRs ([aside from merge
  commits](https://github.com/lightningnetwork/lnd/pull/5543)) add an entry in
  the release notes folder that at least links to PR being added.

* [A new build target itest-race](https://github.com/lightningnetwork/lnd/pull/5542) 
  to help uncover undetected data races with our itests.

* [The itest error whitelist check was removed to reduce the number of failed
  Travis builds](https://github.com/lightningnetwork/lnd/pull/5588).

* [A flake in the Neutrino integration tests with anchor sweeps was 
  addressed](https://github.com/lightningnetwork/lnd/pull/5509).

* [The `lnwire` fuzz tests have been fixed and now run without crashing.](https://github.com/lightningnetwork/lnd/pull/5395)

* [A flake in the race unit
  tests](https://github.com/lightningnetwork/lnd/pull/5659) 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](https://github.com/lightningnetwork/lnd/pull/5553)

* [Clarified 'ErrReservedValueInvalidated' error string](https://github.com/lightningnetwork/lnd/pull/5577)
   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](https://github.com/lightningnetwork/lnd/pull/5526).

## Code Health

### Code cleanup, refactor, typo fixes

* [Refactor the interaction between the `htlcswitch` and `peer` packages for cleaner separation.](https://github.com/lightningnetwork/lnd/pull/5603)

* [Unused error check 
  removed](https://github.com/lightningnetwork/lnd/pull/5537).

* [Shorten Pull Request check list by referring to the CI checks that are 
  in place](https://github.com/lightningnetwork/lnd/pull/5545).

* [Added minor fixes to contribution guidelines](https://github.com/lightningnetwork/lnd/pull/5503).

* [Fixed typo in `dest_custom_records` description comment](https://github.com/lightningnetwork/lnd/pull/5541).

* [Fixed payment test error message.](https://github.com/lightningnetwork/lnd/pull/5559)

* [Bumped version of `github.com/miekg/dns` library to fix a Dependabot
  alert](https://github.com/lightningnetwork/lnd/pull/5576).

* [Fixed timeout flakes in async payment benchmark tests](https://github.com/lightningnetwork/lnd/pull/5579).

* [Flake fix in async bidirectional payment test](https://github.com/lightningnetwork/lnd/pull/5607).

* [Fixed context timeout when closing channels in tests](https://github.com/lightningnetwork/lnd/pull/5616).

* [Fixed transaction not found in mempool flake in commitment deadline itest](https://github.com/lightningnetwork/lnd/pull/5615).

* [Fixed a missing import and git tag in the healthcheck package](https://github.com/lightningnetwork/lnd/pull/5582).

* [Fixed a data race in payment unit test](https://github.com/lightningnetwork/lnd/pull/5573).

* [Missing dots in cmd interface](https://github.com/lightningnetwork/lnd/pull/5535).

* [Link channel point logging](https://github.com/lightningnetwork/lnd/pull/5508)

* [Fixed context leak in integration tests, and properly handled context
  timeout](https://github.com/lightningnetwork/lnd/pull/5646).

* [Removed nested db tx](https://github.com/lightningnetwork/lnd/pull/5643)

## Database

* [Ensure single writer for legacy
  code](https://github.com/lightningnetwork/lnd/pull/5547) when using etcd
  backend.

* [Optimized payment sequence generation](https://github.com/lightningnetwork/lnd/pull/5514/)
  to make LNDs payment throughput (and latency) with better when using etcd.

* [More robust commit queue design](https://github.com/lightningnetwork/lnd/pull/5513)
  to make it less likely that we retry etcd transactions and make the commit
  queue more scalable.

## Performance improvements

* [Update MC store in blocks](https://github.com/lightningnetwork/lnd/pull/5515)
  to make payment throughput better when using etcd.

* [The `lnwire` package now uses a write buffer pool](https://github.com/lightningnetwork/lnd/pull/4884)
  when encoding/decoding messages. Such that most of the heap escapes are fixed,
  resulting in less memory being used when running `lnd`.

## Log system

* [Save compressed log files from logrorate during 
  itest](https://github.com/lightningnetwork/lnd/pull/5354).

## Bug Fixes

A bug has been fixed that would cause `lnd` to [try to bootstrap using the
currnet DNS seeds when in SigNet
mode](https://github.com/lightningnetwork/lnd/pull/5564).

[A validation check for sane `CltvLimit` and `FinalCltvDelta` has been added for `REST`-initiated payments.](https://github.com/lightningnetwork/lnd/pull/5591)

## Documentation 

The [code contribution guidelines have been updated to mention the new
requirements surrounding updating the release notes for each new
change](https://github.com/lightningnetwork/lnd/pull/5613). 

# Contributors (Alphabetical Order)
* Andras Banki-Horvath
* de6df1re
* ErikEk
* Eugene Siegel
* Martin Habovstiak
* Oliver Gugger
* xanoni
* Yong Yu
* Zero-1729