Changelog

Refer to the 2.14 Upgrade Guide for backwards compatibility notes with 2.12.x. Please note that the 2.13.x version was skipped.

Go Version

• 1.26.2

Added

General

• Feature flags in the server configuration (#7866)
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-53.md

JetStream

• Fast-ingest batch publishing (#7778, #7892, #7894, #7945)
  • Allows high-speed publishing of message batches into the server when using a supported client
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-50.md#fast-ingest-batch-publishing
• Repeating & cron-based message schedules (#7504, #7687, #7688)
  • The Nats-Schedule header can now be configured on a repeating basis, i.e. @every 5m, @hourly or using crontab-like syntax
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-51.md
• Scheduled subject sampling (#7506)
  • The Nats-Schedule-Source header allows sampling the contents of the last message in the stream for a given subject, allowing sampling of values at a different rate to the original publisher
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-51.md#subject-sampling
• Scheduled subject rollups (#7559)
  • The Nats-Schedule-Rollup header allows initiating a rollup of the Nats-Schedule-Target subject on a scheduled basis
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-51.md
• Consumer reset API (#7489)
  • It is now possible to reset a consumer back to an earlier sequence number using the $JS.API.CONSUMER.RESET.stream.consumer API without deleting and recreating it
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-60.md#consumer-delivery-state-reset-api
• Domain-aware ack and flow control subjects (#7860)
  • This is disabled by default and can be enabled with the js_ack_fc_v2 feature flag, this will be enabled by default in v2.16
  • In an environment where ACLs are used to control ack or flow control subjects, updates will be required to match the new $JS.ACK.domain.acchash.stream.consumer.> and $JS.FC.domain.acchash.stream.consumer.> subject formats
• Asynchronous stream state snapshots for replicated streams (#7876)
  • Allows stream state snapshots to be taken and written without pausing stream processing, improving tail latencies
  • This is particularly impactful in cases where the stream has a large number of interior deletes
• Ability to disable message deduplication when sourcing (#7651)

Leafnodes

• Leafnode remote configurations can now be added and removed at runtime by reloading the configuration (#7937)
• New ignore_discovered_servers option for leafnode remotes to allow ignoring any leafnode URLs sent by the hub (#8067)

Changed

General

• The traceparent header is no longer modified by the message tracing (#7755)
  • The sentinel Nats-Trace-Dest: trace disabled header value disables all server tracing-related functionality

JetStream

• Consumers now generate a 404 No Messages response when using no_wait but without setting an expiry when there are no pending messages in the stream (#7466)
• Invalid or divergent consumer state is reset to match the stream state on startup, i.e. after unclean shutdowns (#7692)
• Account info, stream info, stream list, consumer info and consumer list API requests are now queued separately, deprioritising them relative to create-update-delete API operations (#7898)

MQTT

• Retained messages can no longer contain the ASCII DEL character (0x7F) in the subject (#8071)

Improved

JetStream

• Sourcing and mirroring from interest and workqueue streams is now supported (#7613)
  • When sourcing or mirroring from an interest or workqueue stream, the server automatically upgrades to a durable consumer with AckFlowControl policy and uses consumer reset where necessary
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-60.md
• End-of-batch commit support for atomic batch publishing (#7403)
  • Batches can now be committed after already having sent the last message with Nats-Batch-Commit: eob, which indicates the batch is to be committed, but this last message is purely used to commit and doesn't get persisted
  • ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-50.md
• Rollups are now allowed if the stream has reached the discard_new_per_subject limit (#7974)
• Raft nodes will step down if overrun (#7853)

Fixed

JetStream

• Raft nodes will no longer start if the snapshot is missing or corrupt, or if the snapshot doesn't align with the remaining log on disk, avoiding potential data loss (#7566, #7580, #7620)
• Filestore operations now handle read and write errors from the filesystem more thoroughly (#7788)
• Filestore recovers from partial purge after hard kill (#7676)
• Consistent Raft group rename when moving to or off R1 (#7802)

Complete Changes

v2.12.0...v2.14.0