v2.11.12

## Changelog

Refer to the [2.11 Upgrade Guide](https://docs.nats.io/release-notes/whats_new/whats_new_211) for backwards compatibility notes with 2.10.x.

### Go Version

- 1.25.6 (#7736)

### Dependencies

- github.com/nats-io/nkeys v0.4.12 (#7578)
- github.com/antithesishq/antithesis-sdk-go v0.5.0-default-no-op (#7604)
- github.com/klauspost/compress v1.18.3 (#7736)
- golang.org/x/crypto v0.47.0 (#7736)
- golang.org/x/sys v0.40.0 (#7736)
- github.com/google/go-tpm v0.9.8 (#7696)
- github.com/nats-io/nats.go v1.48.0 (#7696)

### Added

General

- Added WebSocket-specific ping interval configuration with `ping_internal` in the `websocket` block (#7614)

Monitoring

- Added `tls_cert_not_after` to the `varz` monitoring endpoint for showing when TLS certificates are due to expire (#7709)

### Improved

JetStream

- The scan for the last sourced message sequence when setting up a subject-filtered source is now considerably faster (#7553)
- Consumer interest checks on interest-based streams are now significantly faster when there are large gaps in interest (#7656)
- Creating consumer file stores no longer contends on the stream lock, improving consumer create performance on heavily loaded streams (#7700)
- Recalculating num pending with updated filter subjects no longer gathers and sorts the subject filter list twice (#7772)
- Switching to interest-based retention will now remove no-interest messages from the head of the stream (#7766)

MQTT

- Retained messages will now work correctly even when sourced from a different account and has a subject transform (#7636)

### Fixed

General

- WebSocket connections will now correctly limit the buffer size during decompression (#7625, thanks to Pavel Kokout at Aisle Research)
- The config parser now correctly detects and errors on self-referencing environment variables (#7737)
- Internal functions for handling headers should no longer corrupt message bodies if appended (#7752)

JetStream

- A protocol error caused by an invalid transform of acknowledgement reply subjects when originating from a gateway connection has been fixed (#7579)
- The meta layer will now only respond to peer remove requests after quorum has been reached (#7581)
- Invalid subject filters containing non-terminating full wildcard no longer produce unexpected matches (#7585)
- A data race when creating a stream in clustered mode has been fixed (#7586)
- A panic when processing snapshots with missing nodes or assignments has been fixed (#7588)
- When purging whole message blocks, the subject tracking and scheduled messages are now updated correctly (#7593)
- The filestore will no longer unexpectedly lose writes when `AsyncFlush` is enabled after a process pause (#7594)
- The filestore now will process message removal on disk before updating accounting, which improves error handling (#7595, #7601)
- Raft will no longer allow peer-removing the one remaining peer (#7610)
- A data race has been fixed in the stream health check (#7619)
- Tombstones are now correctly written for recovering the sequences after compacting or purging an almost-empty stream to seq 2 (#7627)
- Combining skip sequences and compactions will no longer overwrite the block at the wrong offset, correcting a `corrupt record state` error (#7627)
- Compactions that reclaim over half of the available space now use an atomic write to avoid losing messages if killed (#7627)
- Filestore compaction should no longer result in `no idx present` cache errors (#7634)
- Filestore compaction now correctly adjusts the high and low sequences for a message block, as well as cleaning up the deletion map accordingly (#7634)
- Potential stream desyncs that could happen during stream snapshotting have been fixed (#7655)
- Raft will no longer allow multiple membership changes to take place concurrently (#7565, #7609)
- Raft will no longer count responses from peer-removed nodes towards quorum (#7589)
- Raft quorum counting has been refactored so the implicit leader ack is now only counted if still a part of the membership (#7600)
- Raft now writes the peer state immediately when handling a peer-remove to ensure the removed peers cannot unexpectedly reappear after a restart (#7602)
- Raft will no longer allow peer-removing the one remaining peer (#7610)
- Add peer operations to Raft can no longer result in disjoint majorities (#7632)
- Raft groups should no longer readmit a previously removed peer if a heartbeat occurs between the peer removal and the leadership transfer (#7649)
- Raft single node elections now transition into leader state correctly (#7642)
- R1 streams will no longer incorrectly drift last sequence when exceeding limits (#7658)
- Deleted streams are no longer wrongfully revived if stalled on an upper-layer catchup (#7668)
- A panic that could happen when receiving a shutdown signal while JetStream is still starting up has been fixed (#7683)
- JetStream usage stats now correctly reflect purged whole blocks when optimising large purges (#7685)
- Recovering JetStream encryption keys now happens independently of the stream index recovery, fixing some cases where the key could be reset unexpectedly if the index is rebuilt (#7678)
- Non-replicated file-based consumers now detect corrupted state on disk and are deleted automatically (#7691)
- Raft no longer allows a repeat vote for the same term after a stepdown or leadership transfer (#7698)
- Replicated consumers are no longer incorrectly deleted if they become leader just as JetStream is about to shut down (#7699)
- Fixed an issue where a single truncated block could prevent storing new messages in the filestore (#7704)
- Fixed a concurrent map iteration/write panic that could occur on WorkQueue streams during partitioning (#7708)
- Fixed a deadlock that could occur on shutdown when adding streams (#7710)
- A data race on mirror consumers has been fixed (#7716)
- JetStream no longer leaks subscriptions in a cluster when a stream import/export is set up that overlaps the `$JS.>` namespace (#7720)
- The filestore will no longer waste CPU time rebuilding subject state for WALs (#7721)
- Configuring `cluster_traffic` in config mode has been fixed (#7723)
- Subject intersection no longer misses certain subjects with specific patterns of overlapping filters, which could affect consumers, num pending calculations etc (#7728, #7741, #7744, #7745)
- Multi-filtered next message lookups in the filestore can now skip blocks when faster to do so (#7750)
- The binary search for start times now handles deleted messages correctly (#7751)
- Consumer updates will now only recalculate num pending when the filter subjects are changed (#7753)
- Consumers on replicated interest or workqueue streams should no longer lose interest or cause desyncs after having their filter subjects updated (#7773)
- Interest-based streams will no longer start more check interest state goroutines when there are existing running ones (#7769)

MQTT

- The maximum payload size is now correctly enforced for MQTT clients (#7555, thanks to @yixianOu)
- Fixed a panic that could occur when reloading config if the user did not have permission to access retained messages (#7596)
- Fixed account mapping for JetStream API requests when traversing non-JetStream-enabled servers (#7598)
- QoS0 messages are now mapped correctly across account imports/exports with subject mappings (#7605)
- Loading retained messages no longer fails after restarting due to last sequence checks (#7616)
- A bug which could corrupt retained messages in clustered deployments has been fixed (#7622)
- Permissions to `$MQTT.` subscriptions are now handled implicitly, with the exception of `deny` ACLs which still permit restriction (#7637)
- A bug where QoS2 messages could not be retrieved after a server restart has been fixed (#7643)

### Complete Changes
 
https://github.com/nats-io/nats-server/compare/v2.11.11...v2.11.12