lnd/docs/release-notes/release-notes-0.15.0.md

# Release Notes

## Payments

Support according to the
[spec](https://github.com/lightningnetwork/lightning-rfc/pull/912) has been
added for [payment metadata in
invoices](https://github.com/lightningnetwork/lnd/pull/5810). If metadata is
present in the invoice, it is encoded as a tlv record for the receiver.

This functionality unlocks future features such as [stateless
invoices](https://lists.linuxfoundation.org/pipermail/lightning-dev/2021-September/003236.html).

## Security

* [Misconfigured ZMQ
  setup now logs a warning](https://github.com/lightningnetwork/lnd/pull/5710).

## Taproot

The internal on-chain wallet of `lnd` is now able to create and spend from
[Taproot (SegWit v1)
addresses](https://github.com/lightningnetwork/lnd/pull/6263). Using
`lncli newaddress p2tr` will create a new BIP-0086 keyspend only address and
then watch it on chain. Taproot script spends are also supported through the
`signrpc.SignOutputRaw` RPC (`/v2/signer/signraw` in REST).

The `walletrpc.SignPsbt` RPC now also supports [Taproot PSBT
signing](https://github.com/lightningnetwork/lnd/pull/6450) to fully support
remote signing with Taproot outputs. 

The internal version of the `aezeed` [was bumped to `1` to mark new seeds that
were created after introducing the Taproot key
derivation](https://github.com/lightningnetwork/lnd/pull/6524) to simplify
detecting Taproot compatibility of a seed.

## MuSig2

The [`signrpc.Signer` RPC service now supports EXPERIMENTAL MuSig2
signing](https://github.com/lightningnetwork/lnd/pull/6361).

More information can be found in the [MuSig2 documentation](../musig2.md).
Note that the MuSig2 BIP is not final yet and therefore the MuSig2 API must be
considered to be HIGHLY EXPERIMENTAL and subject to change in upcoming
releases. Backward compatibility is not guaranteed!

## `lncli`

* Add [auto-generated command-line completions](https://github.com/lightningnetwork/lnd/pull/4177) 
  for Fish shell.  

* Add [chan_point flag](https://github.com/lightningnetwork/lnd/pull/6152)
  to closechannel command.

* Add [private status](https://github.com/lightningnetwork/lnd/pull/6167)
  to pendingchannels response.

* [Update description for `state` command](https://github.com/lightningnetwork/lnd/pull/6237).

* Add [update node announcement](https://github.com/lightningnetwork/lnd/pull/5587)
  for updating and propagating node information.

* Add [--socksproxy](https://github.com/lightningnetwork/lnd/pull/6422)
  to allow for RPC calls via Tor.

* [Hop hints are now opt in when using `lncli
  addinvoice`](https://github.com/lightningnetwork/lnd/pull/6523). Users now
  need to explicitly specify the `--private` flag.

* A new [`constrainmacaroon` command was
  added](https://github.com/lightningnetwork/lnd/pull/6529) that allows
  caveats/restrictions to be added to an existing macaroon (instead of needing
  to bake a new one). 

## Neutrino

[Neutrino now suports BIP
155](https://github.com/lightningnetwork/lnd/pull/6468), allowing it to connect
to Bitcoin nodes that advertise a Tor v3 onion service address.

[A new neutrino sub-server](https://github.com/lightningnetwork/lnd/pull/5652)
capable of status checks, adding, disconnecting and listing peers, fetching
compact filters and block/block headers.

## Btcwallet

* [Add option to configure the block and transaction subscription 
  notifications from bitcoind to be obtained through polling of the RPC 
  interface instead of using ZMQ](https://github.com/lightningnetwork/lnd/pull/6345)

## Bug Fixes

* [Pipelining an UpdateFulfillHTLC message now only happens when the related UpdateAddHTLC is locked-in.](https://github.com/lightningnetwork/lnd/pull/6246)

* [Fixed an inactive invoice subscription not removed from invoice
  registry](https://github.com/lightningnetwork/lnd/pull/6053). When an invoice
  subscription is created and canceled immediately, it could be left uncleaned
  due to the cancel signal is processed before the creation. It is now properly
  handled by moving creation before deletion.   

* When the block height+delta specified by a network message is greater than
  the gossiper's best height, it will be considered as premature and ignored.
  [These premature messages are now saved into a cache and processed once the
  height has reached.](https://github.com/lightningnetwork/lnd/pull/6054)

* [Fixed failure to limit our number of hop hints in private invoices](https://github.com/lightningnetwork/lnd/pull/6236).
  When a private invoice is created, and the node had > 20 (our hop hint limit)
  private channels with inbound > invoice amount, hop hint selection would add
  too many hop hints. When a node had many channels meeting this criteria, it 
  could result in an "invoice too large" error when creating invoices. Hints 
  are now properly limited to our maximum of 20.

* [Fixed an edge case where the lnd might be stuck at starting due to channel
  arbitrator relying on htlcswitch to be started
  first](https://github.com/lightningnetwork/lnd/pull/6214).

* [Fixed an issue where invoice notifications could be missed when using the
   SubscribeSingleInvoice or SubscribeNotifications rpcs.](https://github.com/lightningnetwork/lnd/pull/6477)

* [Fixed crash in MuSig2Combine](https://github.com/lightningnetwork/lnd/pull/6502)

* [Added signature length
  validation](https://github.com/lightningnetwork/lnd/pull/6314) when calling
  `NewSigFromRawSignature`.

* [Fixed deadlock in invoice
  registry](https://github.com/lightningnetwork/lnd/pull/6332).

* [Fixed an issue that would cause wallet UTXO state to be incorrect if a 3rd
  party sweeps our anchor
  output](https://github.com/lightningnetwork/lnd/pull/6274).

* [Fixed node shutdown in forward interceptor itests](https://github.com/lightningnetwork/lnd/pull/6362).

* [Fixed a bug that would cause lnd to be unable to parse certain PSBT blobs](https://github.com/lightningnetwork/lnd/pull/6383).
 
* [Use normal TCP resolution, instead of Tor DNS resolution, for addresses
   using the all-interfaces IP](https://github.com/lightningnetwork/lnd/pull/6376).

* [Fixed a bug in the `btcwallet` that caused an error to be shown for
  `lncli walletbalance` in existing wallets after upgrading to
  Taproot](https://github.com/lightningnetwork/lnd/pull/6379).

* [Fixed a data race in the websocket proxy
  code](https://github.com/lightningnetwork/lnd/pull/6380).

* [Fixed race condition resulting in MPP payments sometimes getting stuck
  in-flight](https://github.com/lightningnetwork/lnd/pull/6352).

* [Fixed a panic in the Taproot signing part of the `SignOutputRaw` RPC that
  occurred when not all UTXO information was
  specified](https://github.com/lightningnetwork/lnd/pull/6407).

* [Fixed P2TR addresses not correctly being detected as
  used](https://github.com/lightningnetwork/lnd/pull/6389).

* [Fixed incorrect PSBT de-serialization for transactions with no
  inputs](https://github.com/lightningnetwork/lnd/pull/6428).

* [Fixed a spec-compliance issue where lnd was not allowing cooperative
close to continue after a peer disconnect](https://github.com/lightningnetwork/lnd/pull/6419).

* [A subsystem hand-off between the contractcourt and htlcswitch has been fixed by adding a persistence layer. This avoids a rare edge case
from occurring that would result in an erroneous force close.](https://github.com/lightningnetwork/lnd/pull/6250)

* [Ignore addresses with unknown types in NodeAnnouncements](
  https://github.com/lightningnetwork/lnd/pull/6435)

* [Taproot wallet inputs can also be used to fund
  channels](https://github.com/lightningnetwork/lnd/pull/6521)

* [Fixed an intermittent panic that would occur due to a violated assumption with our
  underlying database.](https://github.com/lightningnetwork/lnd/pull/6547)

## Routing

* [Add a new `time_pref` parameter to the QueryRoutes and SendPayment APIs](https://github.com/lightningnetwork/lnd/pull/6024) that
  allows the caller to control the trade-off between payment speed and cost in
  pathfinding.

## Misc

* [An example systemd service file](https://github.com/lightningnetwork/lnd/pull/6033)
  for running lnd alongside a bitcoind service is now provided in
  `contrib/init/lnd.service`.

* [Allow disabling migrations if the database backend passed to `channeldb` was
  opened in read-only mode](https://github.com/lightningnetwork/lnd/pull/6084).

* [Disable compiler optimizations](https://github.com/lightningnetwork/lnd/pull/6105)
  when building `lnd-debug` and `lncli-debug`. It helps when stepping through the code
  with a debugger like Delve.
  
* A new command `lncli leaseoutput` was [added](https://github.com/lightningnetwork/lnd/pull/5964).

* [Consolidated many smaller docs/typo/trivial fixes from PRs that were stuck
  in review because of unmet contribution guideline
  requirements](https://github.com/lightningnetwork/lnd/pull/6080).

* [A nightly build of the `lnd` docker image is now created
  automatically](https://github.com/lightningnetwork/lnd/pull/6160).
  
* Add default values to [walletrpc.ListUnspent RPC call](https://github.com/lightningnetwork/lnd/pull/6190).

* [Add `.vs/` folder to `.gitignore`](https://github.com/lightningnetwork/lnd/pull/6178). 

* [Chain backend healthchecks disabled for --nochainbackend mode](https://github.com/lightningnetwork/lnd/pull/6184)

* [The `tlv` package was refactored into its own Golang
  submodule](https://github.com/lightningnetwork/lnd/pull/6283).

* The `tor` package was refactored into its own Golang submodule and a new
  process for changing and tagging submodules was introduced in a series of
  3 PRs ([#6350](https://github.com/lightningnetwork/lnd/pull/6350),
  [#6355](https://github.com/lightningnetwork/lnd/pull/6350) and
  [#6356](https://github.com/lightningnetwork/lnd/pull/6356)).

* [Source repository can now be specified for Docker image builds](https://github.com/lightningnetwork/lnd/pull/6300)

* [The new `btcsuite/btcd/btcec/v2` and the moved `btcsuite/btcd/btcutil`
  modules were integrated into `lnd` as a preparation for basic Taproot
  support](https://github.com/lightningnetwork/lnd/pull/6285).

* [Make etcd leader election session
  TTL](https://github.com/lightningnetwork/lnd/pull/6342) configurable.

* [Fix race condition in the htlc interceptor unit
  test](https://github.com/lightningnetwork/lnd/pull/6353).

* [A new config option, `pending-commit-interval` is
  added](https://github.com/lightningnetwork/lnd/pull/6186). This value
  specifies the maximum duration it allows for a remote peer to respond to a
  locally initiated commitment update.

* [`macos` and `apple` Makefile tasks have been added.](https://github.com/lightningnetwork/lnd/pull/6373)

  The `macos` task uses `gomobile` to build an `XCFramework` that can be used to
  embed lnd to macOS apps, similar to how the `ios` task builds for iOS.

  The `apple` task uses `gomobile` to build an `XCFramework` that can be used to
  embed lnd to both iOS and macOS apps.

* [The CI and build infrastructure for the project has transitioned to using Go 1.18](https://github.com/lightningnetwork/lnd/pull/6340).

* [Announce the keysend feature bit in NodeAnnouncement if `--accept-keysend` 
  is set](https://github.com/lightningnetwork/lnd/pull/6414).

* [Fix a flaky unit test in the `chainview`
  package](https://github.com/lightningnetwork/lnd/pull/6354).

* [Adds a new config option for adding a specific peer at startup](https://github.com/lightningnetwork/lnd/pull/5157).

* [Add a new method in `tlv` to encode an uint64/uint32 field using `BigSize`
  format.](https://github.com/lightningnetwork/lnd/pull/6421)

* [Add new `bitcoind.config` and `bitcoind.rpccookie`
  options](https://github.com/lightningnetwork/lnd/pull/6064) to allow
  specifying non-default paths for the configuration and RPC cookie files.

* [Clarify comment](https://github.com/lightningnetwork/lnd/pull/6481) on 
  `chainnotifier.RegisterConfirmationsNtfn`.

* [The experimental MuSig2 API now also has a `MuSig2Cleanup` RPC that allows
  the in-memory state to be cleaned up early if a session isn't expected to
  succeed anymore](https://github.com/lightningnetwork/lnd/pull/6495).

* [Some of the invoice update logic has been refactored to be less verbose.](https://github.com/lightningnetwork/lnd/pull/6415)

* [Clarify error msg when bitcoind cookie file is missing](https://github.com/lightningnetwork/lnd/pull/6536).

* [Minor fix](https://github.com/lightningnetwork/lnd/pull/6535) to
  how bitcoind.rpccookie and bitocind.config are parsed from config file.

## RPC Server

* [Add value to the field
  `remote_balance`](https://github.com/lightningnetwork/lnd/pull/5931) in
  `pending_force_closing_channels` under `pendingchannels` whereas before was
  empty(zero).
* The graph's [diameter is calculated](https://github.com/lightningnetwork/lnd/pull/6066)
  and added to the `getnetworkinfo` output.

* [Add dev only RPC subserver and the devrpc.ImportGraph
  call](https://github.com/lightningnetwork/lnd/pull/6149)
  
* [Extend](https://github.com/lightningnetwork/lnd/pull/6177) the HTLC
  interceptor API to provide more control over failure messages. With this
  change, it allows encrypted failure messages to be returned to the sender.
  Additionally it is possible to signal a malformed htlc.

* Add an [always on](https://github.com/lightningnetwork/lnd/pull/6232) mode to
  the HTLC interceptor API. This enables interception applications where every
  packet must be intercepted.

* Add [destination output information](https://github.com/lightningnetwork/lnd/pull/5476)
  to the transaction structure returned from the RPC `GetTransactions` and when
  subscribed with `SubscribeTransactions`.

* [Support for making routes with the legacy onion payload format via `SendToRoute` has been removed.](https://github.com/lightningnetwork/lnd/pull/6385)

* Close a gap in the HTLC interceptor API by [intercepting htlcs in the on-chain
  resolution flow](https://github.com/lightningnetwork/lnd/pull/6219) too.

* [Expose](https://github.com/lightningnetwork/lnd/pull/6454) always on mode of
  the HTLC interceptor API through GetInfo.

* [The `lnrpc.ListPayments` RPC now has an optional `count_total_payments`
  parameter that will cause the `total_num_payments` response field to be set
  to the total number of payments (complete and incomplete) that are currently
  in the payment database](https://github.com/lightningnetwork/lnd/pull/6463).

* [Remove `confirmation_height` field from PendingChannel proto](https://github.com/lightningnetwork/lnd/pull/6472)

* [The `walletrpc.ListLeases` RPC (`lncli wallet listleases`) now shows the
  pkScript and value of a leased
  output](https://github.com/lightningnetwork/lnd/pull/6528).

## Database

* [Add ForAll implementation for etcd to speed up
  graph cache at startup](https://github.com/lightningnetwork/lnd/pull/6136)

* [Improve validation of a PSBT packet when handling a request to finalize it.](https://github.com/lightningnetwork/lnd/pull/6217)

* [Add new Peers subserver](https://github.com/lightningnetwork/lnd/pull/5587) with a new endpoint for updating the `NodeAnnouncement` data without having to restart the node.

* Add [htlc expiry protection](https://github.com/lightningnetwork/lnd/pull/6212)
to the htlc interceptor API.

* In order to safely advance commitment state, `lnd` saves the past states and
  constructs a justice transaction in case of a remote breach. The states can
  grow very large on disk given a busy operating channel, [which is now changed
  with a space deduction over (at least) 96 percents.](https://github.com/lightningnetwork/lnd/pull/6347) 

* Aside from the above database optimization, two new fields,
  [`InitialLocalBalance` and `InitialRemoteBalance` have been added to each
  channel to keep track of the push
  amount](https://github.com/lightningnetwork/lnd/pull/6551). For open
  channels, these values are taken from reading its past states. For
  historical(closed) channels, they are patched with empty values as the
  channels' past states have been deleted during closing.

* [Mobile builds now expose main sub-servers by default](https://github.com/lightningnetwork/lnd/pull/6464).
  All API methods have prefixed the generated methods with the subserver name.
  This is required to support subservers with name conflicts.

## Documentation

* Improved instructions on [how to build lnd for mobile](https://github.com/lightningnetwork/lnd/pull/6085).
* [Log force-close related messages on "info" level](https://github.com/lightningnetwork/lnd/pull/6124).

* [Add list of build tags](https://github.com/lightningnetwork/lnd/pull/6486)
  to the install instructions.

## Monitoring

A new [flag (`--prometheus.perfhistograms`) has been added to enable export of
gRPC performance metrics (latency to process `GetInfo`, etc)](https://github.com/lightningnetwork/lnd/pull/6224).

## Code Health

### Code cleanup, refactor, typo fixes

* [Refactored itest to better manage contexts inside integration tests](https://github.com/lightningnetwork/lnd/pull/5756).

* [Fix itest not picking up local config file or creating directories in home
  dir of the user](https://github.com/lightningnetwork/lnd/pull/6202).

* [A refactor of `SelectHopHints`](https://github.com/lightningnetwork/lnd/pull/6182) 
  allows code external to lnd to call the function, where previously it would 
  require access to lnd's internals.

* [rpc-check fails if it finds any changes](https://github.com/lightningnetwork/lnd/pull/6207/)
  including new and deleted files.

* [The `golangci-lint` package was updated and new linters were
  enabled](https://github.com/lightningnetwork/lnd/pull/6244).

* The linting process now runs [inside a docker
  container](https://github.com/lightningnetwork/lnd/pull/6248) to fix
  versioning issues between projects.

* The [`whitespace` linter](https://github.com/lightningnetwork/lnd/pull/6270)
  was enabled to make sure multi-line `if` conditions and function/method
  declarations are followed by an empty line to improve readability.
  **Note to developers**: please make sure you delete the old version of
  `golangci-lint` in your `$GOPATH/bin` directory. `make lint` does not
  automatically replace it with the new version if the binary already exists!
  
* [`ChannelLink` in the `htlcswitch` now performs a 1-way handoff via a temporary map with its `ChannelArbitrator`.](https://github.com/lightningnetwork/lnd/pull/6322)

* [The channel-commit-interval is now clamped to a reasonable timeframe of 1h.](https://github.com/lightningnetwork/lnd/pull/6220)

* [A function in the gossiper `processNetworkAnnouncements` has been refactored for readability and for future deduplication efforts.](https://github.com/lightningnetwork/lnd/pull/6278)

# Contributors (Alphabetical Order)

* 3nprob
* Alyssa Hertig
* Andras Banki-Horvath
* Andreas Schjønhaug
* asvdf
* bitromortac
* Bjarne Magnussen
* BTCparadigm
* Carl Dong
* Carla Kirk-Cohen
* Carsten Otto
* Dan Bolser
* Daniel McNally
* Elle Mouton
* ErikEk
* Eugene Siegel
* Evan Kaloudis
* Hampus Sjöberg
* henta
* hieblmi
* Joost Jager
* Jordi Montes
* LightningHelper
* Liviu
* mateuszmp
* Naveen Srinivasan
* Olaoluwa Osuntokun
* randymcmillan
* Rong Ou
* Thebora Kompanioni
* Tommy Volk
* Torkel Rogstad
* Vsevolod Kaganovych
* Yong Yu