--- title: Release Notes description: Couchbase Sync Gateway pubDate: 2026-08-17T09:53:44.266Z antora: editUrl: https://github.com/couchbase/docs-sync-gateway/edit/release/4.0/modules/product-notes/pages/release-notes.adoc xref: xref:4.0@sync-gateway:product-notes:release-notes.adoc[] --- [Consult the llms.txt file for a full list of contents](/llms.txt) [View original HTML](/sync-gateway/4.0/product-notes/release-notes.html) # Release Notes Quicklinks [Release 3.3](../../3.3/product-notes/release-notes.md) | [Release 3.2](../../3.2/release-notes.md) | [Release 3.1](../../3.1/release-notes.md) | [Release 3.0](../../3.0/release-notes.md) | [Archived documentation](https://docs-archive.couchbase.com/home/index.html) > Couchbase Sync Gateway > This content describes the key features and changes implemented by release 4.0 of Couchbase Sync Gateway > [!CAUTION] > One Way Upgrade > > The migration to a 4.x configuration is a ONE WAY process — see: [Upgrading](../upgrading.md) for more. ## [](#maint-4-0-7)4.0.7 — July 2026 > [!IMPORTANT] > If you use Sync Gateway 4.0.5 or 4.0.6, upgrade to this release to receive critical fixes. ### [](#fixed-issues)Fixed Issues * [CBG-5255 — Upgrading from non persistent config to persistent config will trigger database requiring resync](https://jira.issues.couchbase.com/browse/CBG-5255) * [CBG-5287 — \_changes feeds with active\_only=true and limit parameters can miss expected changes with revocations](https://jira.issues.couchbase.com/browse/CBG-5287) * [CBG-5361 — Panic in revoked feed handling](https://jira.issues.couchbase.com/browse/CBG-5361) * [CBG-5368 — Problem with channel removal macro expansion when channel names have . in them](https://jira.issues.couchbase.com/browse/CBG-5368) * [CBG-5383 — Resync regenerate sequences will not set \_default metadata id when finished](https://jira.issues.couchbase.com/browse/CBG-5383) * [CBG-5453 — Subdoc operation failure on multiple channel removal](https://jira.issues.couchbase.com/browse/CBG-5453) * [CBG-5553 — activeOnly replication can miss documents for channels over the pagination limit](https://jira.issues.couchbase.com/browse/CBG-5553) ### [](#enhancements)Enhancements * [CBG-5394 — REST endpoint for pruning document channel history](https://jira.issues.couchbase.com/browse/CBG-5394) * [CBG-5396 — REST endpoint for pruning user channel history](https://jira.issues.couchbase.com/browse/CBG-5396) ### [](#known-issues)Known Issues None for this release. ### [](#deprecations)Deprecations None for this release. ## [](#4-0-4april-2026)4.0.4 — April 2026 ### [](#maint-4-0-4)Fixed Issues * [CBG-5173 — /db/\_index\_init panics if db started offline](https://jira.issues.couchbase.com/browse/CBG-5173) * [CBG-5202 — Remote wins conflict resoultion results in new revID](https://jira.issues.couchbase.com/browse/CBG-5202) ### [](#enhancements-2)Enhancements * [CBG-5157 — Support EdDSA tokens for OIDC/JWTs](https://jira.issues.couchbase.com/browse/CBG-5157) * [CBG-5214 — silently handle cbl-js ping blip requests](https://jira.issues.couchbase.com/browse/CBG-5214) ### [](#known-issues-2)Known Issues None for this release. ### [](#deprecations-2)Deprecations None for this release. ## [](#4-0-3february-2026)4.0.3 — February 2026 ### [](#maint-4-0-3)Fixed Issues * [CBG-4949 — Duplicate conflict logging during legacy rev processing](https://jira.issues.couchbase.com/browse/CBG-4949) * [CBG-4998 — Import feed panics for docs with CV in \_sync.rev.ver but no \_vv xattr](https://jira.issues.couchbase.com/browse/CBG-4998) * [CBG-5016 — Panic in \_config?include\_runtime=true endpoint when database has failed to start](https://jira.issues.couchbase.com/browse/CBG-5016) * [CBG-5042 — Couchbase Server timeout error causes panic in GetUser](https://jira.issues.couchbase.com/browse/CBG-5042) * [CBG-5055 — Non-integer sequence numbers are incorrectly encoded for norev messages for CBL](https://jira.issues.couchbase.com/browse/CBG-5055) * [CBG-5068 — Corrupted document metadata causes unchecked subslice panic in sendRevision→toHistory(docRev.History)](https://jira.issues.couchbase.com/browse/CBG-5068) * [CBG-5107 — Channel information unavailable for non-current revisions](https://jira.issues.couchbase.com/browse/CBG-5107) * [CBG-5108 — Rev cache can associate stale body with cv or revtreeID when loading revision body backups for non-current revs](https://jira.issues.couchbase.com/browse/CBG-5108) * [CBG-5132 — Clients fetching a delta can panic when the revision cache is disabled](https://jira.issues.couchbase.com/browse/CBG-5132) * [CBG-5135 — Current revision attachments can be loaded when loading backup rev by CV](https://jira.issues.couchbase.com/browse/CBG-5135) * [CBG-5136 — Backup revs loaded from bucket in CV pathway incorrectly assigning deleted status to document revision](https://jira.issues.couchbase.com/browse/CBG-5136) * [CBG-5146 — replacement revs never utilized for unfiltered replications](https://jira.issues.couchbase.com/browse/CBG-5146) ### [](#enhancements-3)Enhancements * [CBG-4765 — Caching performance improvements](https://jira.issues.couchbase.com/browse/CBG-4765) * [CBG-5092 — Increase websocket control frame timeouts](https://jira.issues.couchbase.com/browse/CBG-5092) ### [](#known-issues-3)Known Issues None for this release. ### [](#deprecations-3)Deprecations None for this release. ## [](#4-0-2december-2025)4.0.2 — December 2025 ### [](#maint-4-0-2)Fixed Issues * [CBG-5007 — \_ping (and all endpoints) acquire ServerContext.lock.RLock and blocks if the write lock is acquired](https://jira.issues.couchbase.com/browse/CBG-5007) * [CBG-5026 — Resync on documents last mutated prior to Sync Gateway 4.0 will fail](https://jira.issues.couchbase.com/browse/CBG-5026) * [CBG-5027 — Have rev cache lock and rev cache value unlocks use defer where possible](https://jira.issues.couchbase.com/browse/CBG-5027) * [CBG-5029 — Panic during memory based cache eviction can deadlock revision cache shard](https://jira.issues.couchbase.com/browse/CBG-5029) ### [](#enhancements-4)Enhancements * [CBG-5034 — Synchronize Computation of Deltas](https://jira.issues.couchbase.com/browse/CBG-5034) ### [](#known-issues-4)Known Issues None for this release. ### [](#deprecations-4)Deprecations None for this release. ## [](#4-0-1november-2025)4.0.1 — November 2025 ### [](#maint-4-0-1)Fixed Issues * [CBG-4972 — Don't set SameSite=None when no TLS is used](https://jira.issues.couchbase.com/browse/CBG-4972) ### [](#enhancements-5)Enhancements * [CBG-4969 — Allow cookieless auth from cbl-js](https://jira.issues.couchbase.com/browse/CBG-4969) ### [](#known-issues-5)Known Issues None for this release. ### [](#deprecations-5)Deprecations None for this release. ## [](#4-0-0october-2025)4.0.0 — October 2025 ### [](#maint-4-0-0)Fixed Issues * [CBG-4767 - Make raw doc endpoint return persisted state of document](https://jira.issues.couchbase.com/browse/CBG-4767) * [CBG-4768 - Silence logging for Admin API expvar requests](https://jira.issues.couchbase.com/browse/CBG-4768) ### [](#enhancements-6)Enhancements * [CBG-3203 - Shrink revision tree storage by removing channel information](https://jira.issues.couchbase.com/browse/CBG-3203) * [CBG-4206 - Store attachment metadata in \_globalSync xattr](https://jira.issues.couchbase.com/browse/CBG-4206) * [CBG-4729 - Add metrics for deleted documents](https://jira.issues.couchbase.com/browse/CBG-4729) * [CBG-4737 - Disallow basic auth command line flags](https://jira.issues.couchbase.com/browse/CBG-4737) * [CBG-4754 - Silence debug logging for ping and metrics endpoints](https://jira.issues.couchbase.com/browse/CBG-4754) * [CBG-4757 - Improve ISGR reconnect logging](https://jira.issues.couchbase.com/browse/CBG-4757) ### [](#known-issues-6)Known Issues * [CBG-4772 - User xattr only update results in new HLV entry](https://jira.issues.couchbase.com/browse/CBG-4772) * [CBG-4844 - Attachment audit events do not show CV, only RevTree ID](https://jira.issues.couchbase.com/browse/CBG-4844) * [CBG-4887 - Orphaned attachments can be left in bucket after removal](https://jira.issues.couchbase.com/browse/CBG-4887) * [CBG-4939 - Couchbase Lite 4.0 with Sync Gateway versions before 4.0 is unsupported](https://jira.issues.couchbase.com/browse/CBG-4939) ### [](#deprecations-6)Deprecations * [CBG-3796 - Disallow enable\_star\_channel=false](https://jira.issues.couchbase.com/browse/CBG-3796) * [CBG-4316 - Disallow allow\_conflicts=true](https://jira.issues.couchbase.com/browse/CBG-4316) * [CBG-4726 - Disallow enable\_shared\_bucket\_access=false](https://jira.issues.couchbase.com/browse/CBG-4726) > [!NOTE] > For an overview of the latest features offered in Sync Gateway 4.0.0, see [New in 4.0](../whatsnew.md). ## [](#upgrading)Upgrading For more on upgrading — see: [Upgrading](../upgrading.md) --- ##### ## [](#related-content)Related Content ###### [](#-2) API Topics * [Public REST API](../rest-api/rest-api.md) * [Admin REST API](../rest-api/rest-api-admin.md) * [Metrics REST API](../rest-api/rest-api-metrics.md) ###### [](#-3) Reference * [Bootstrap](../configuration/configuration-schema-bootstrap.md) * [Database](../configuration/configuration-schema-database.md) * [Database Security](../configuration/configuration-schema-db-security.md) * [Access Control](../configuration/configuration-schema-access-control.md) * [Import Filter](../configuration/configuration-schema-import-filter.md) * [Inter-Sync Gateway Replication](../configuration/configuration-schema-isgr.md) * [Legacy Pre-3.0 Configuration](../configuration/configuration-properties-legacy.md) ###### [](#-4) Community [Mobile Forum](https://forums.couchbase.com/c/mobile/14) | [Blog](https://blog.couchbase.com/) | [Blog (Mobile)](https://blog.couchbase.com/category/couchbase-mobile/?ref=blog-menu) | [Tutorials](https://docs.couchbase.com/tutorials/)