--- title: Couchbase Lite Release Notes description: Couchbase Lite on Swift pubDate: 2026-08-17T09:53:44.266Z antora: editUrl: https://github.com/couchbase/docs-couchbase-lite/edit/release/4.0/modules/swift/pages/releasenotes.adoc xref: xref:4.0@couchbase-lite:swift:releasenotes.adoc[] --- [Consult the llms.txt file for a full list of contents](/llms.txt) [View original HTML](/couchbase-lite/4.0/swift/releasenotes.html) # Couchbase Lite Release Notes ## [](#maint-4-0-4)4.0.4 — May 2026 Version 4.0.4 for Swift delivers the following features and enhancements: ### [](#enhancements)Enhancements * [CBL-7989 — Upgrade SQLite to 3.53.0](https://jira.issues.couchbase.com/browse/CBL-7989) * [CBL-8076 — Improve replicator WebSocket close completion when the server fails to acknowledge close](https://jira.issues.couchbase.com/browse/CBL-8076) * [CBL-8183 — Upgrade mbedTLS to 3.6.6](https://jira.issues.couchbase.com/browse/CBL-8183) ### [](#issues-and-resolutions)Issues and Resolutions * [CBL-7992 — Partial value index creation failing when using compound expressions in WHERE clause](https://jira.issues.couchbase.com/browse/CBL-7992). * [CBL-8159 — Result.data(as:dataKey:) dropping optional properties when using dataKey](https://jira.issues.couchbase.com/browse/CBL-8159) ### [](#known-issues)Known Issues None for this release ### [](#deprecations)Deprecations None for this release > [!NOTE] > For an overview of the latest features offered in Couchbase Lite 4.0, see [New in 4.0](../cbl-whatsnew.md) ## [](#maint-4-0-3)4.0.3 — February 2026 Version 4.0.3 for Swift delivers the following features and enhancements: ### [](#enhancements-2)Enhancements * [CBL-7750 — Update mbedTLS to 3.6.5](https://jira.issues.couchbase.com/browse/CBL-7750) * [CBL-7775 — Increase Replicator's WebSocket PING / PONG timeout](https://jira.issues.couchbase.com/browse/CBL-7775) ### [](#issues-and-resolutions-2)Issues and Resolutions * [CBL-5298 — Fix SQL++ parser failure for IN operator](https://jira.issues.couchbase.com/browse/CBL-5298) * [CBL-7661 — Increase Replicator Database Pool Borrow Timeout](https://jira.issues.couchbase.com/browse/CBL-7661) * [CBL-7799 — "Invalid version string" exception from replicator when pulling a merged conflict version](https://jira.issues.couchbase.com/browse/CBL-7799) ### [](#known-issues-2)Known Issues None for this release ### [](#deprecations-2)Deprecations None for this release > [!NOTE] > For an overview of the latest features offered in Couchbase Lite 4.0, see [New in 4.0](../cbl-whatsnew.md) ## [](#maint-4-0-2)4.0.2 — December 2025 Version 4.0.2 for Swift delivers the following features and enhancements: ### [](#enhancements-3)Enhancements None for this release ### [](#fixed-issues)Fixed Issues * [CBL-7681 — Crash with 'Can't retain immutable Value' Error after upgrading from 3.0.3 to 4.0.0](https://jira.issues.couchbase.com/browse/CBL-7681) ### [](#known-issues-3)Known Issues None for this release ### [](#breaking-changes)Breaking Changes None for this release ### [](#deprecations-3)Deprecations None for this release > [!NOTE] > For an overview of the latest features offered in Couchbase Lite 4.0, see [New in 4.0](../cbl-whatsnew.md) ## [](#maint-4-0-1)4.0.1 — November 2025 Version 4.0.1 for Swift delivers the following features and enhancements: ### [](#enhancements-4)Enhancements None for this release ### [](#fixed-issues-2)Fixed Issues * [CBL-7658 — Peer IP resolution may time out when the service is discovered on an IPv6 link-local interface](https://jira.issues.couchbase.com/browse/CBL-7658) * [CBL-7660 — Resolved an issue in MultipeerReplicator.](https://jira.issues.couchbase.com/browse/CBL-7660) ### [](#known-issues-4)Known Issues None for this release ### [](#breaking-changes-2)Breaking Changes None for this release ### [](#deprecations-4)Deprecations None for this release > [!NOTE] > For an overview of the latest features offered in Couchbase Lite 4.0, see [New in 4.0](../cbl-whatsnew.md) ## [](#maint-4-0-0)4.0.0 — October 2025 Version 4.0.0 for Swift delivers the following features and enhancements: ### [](#enhancements-5)Enhancements * [CBL-7568 — New Version Vector Database](https://issues.couchbase.com/browse/CBL-7568) * [CBL-6569 — Disabled SQLite's mmap by default](https://issues.couchbase.com/browse/CBL-6569) * [CBL-7279 — Support timestamp property in Document](https://issues.couchbase.com/browse/CBL-7279) * [CBL-7283 — Support Last-Write-Wins as the default Conflict Resolver for Replicator](https://issues.couchbase.com/browse/CBL-7283) * [CBL-7348 — Update Database APIs to Return or Throw NotOpen Error for Closed Database Cases](https://issues.couchbase.com/browse/CBL-7348) ### [](#fixed-issues-3)Fixed Issues * [CBL-6504 — Query parser regression related to brackets](https://issues.couchbase.com/browse/CBL-6504) * [CBL-6513 — Race creating the expiration column in a collection table](https://issues.couchbase.com/browse/CBL-6513) * [CBL-7413 — Wrong error shown when using mismatch collections in Replicator](https://issues.couchbase.com/browse/CBL-7413) * [CBL-7467 — TLS ClientHello missing Server Name when network interface is specified](https://issues.couchbase.com/browse/CBL-7467) ### [](#known-issues-5)Known Issues * [CBL-7572 — Database.Copy() doesn't convert Self-Source-ID to the original Source ID](https://issues.couchbase.com/browse/CBL-7572) * [CBL-7573 — Couchbase Lite 4.0 is allowed to connect to Sync Gateway 3.2.6/3.3.0](https://issues.couchbase.com/browse/CBL-7573) * [CBL-7654 — MultipeerCertificateAuthenticator created with root certs fails to validate peer certificates](https://jira.issues.couchbase.com/browse/CBL-7654) ### [](#breaking-changes-3)Breaking Changes * [CBL-6596 — Vector Search Extension 2.0.0 Required for Couchbase Lite 4.0.0](https://jira.issues.couchbase.com/browse/CBL-6596) * [CBL-7288 — Remove Deprecated Database APIs](https://issues.couchbase.com/browse/CBL-7288) * [CBL-7292 — Removed: Deprecated Remove Change Listener APIs](https://issues.couchbase.com/browse/CBL-7292) * [CBL-7296 — Removed: Deprecated QueryBuilder APIs](https://issues.couchbase.com/browse/CBL-7296) * [CBL-7300 — Remove Deprecated Collection Management API in ReplicatorConfiguration](https://issues.couchbase.com/browse/CBL-7300) * [CBL-7304 — Removed: Deprecated TLSIdentity's createIdentity with isServer boolean flag](https://issues.couchbase.com/browse/CBL-7304) * [CBL-7313 — Removed: Deprecated Logging APIs](https://issues.couchbase.com/browse/CBL-7313) * [CBL-7378 — Removed: DatabaseConfiguration's mmapEnabled property](https://issues.couchbase.com/browse/CBL-7378) * [CBL-7390 — Removed: Deprecated Default Constants](https://issues.couchbase.com/browse/CBL-7390) * [CBL-7571 — Removed Deprecated Replicator and Listener APIs](https://issues.couchbase.com/browse/CBL-7571) ### [](#deprecations-5)Deprecations None for this release > [!NOTE] > For an overview of the latest features offered in Couchbase Lite 4.0, see [New in 4.0](../cbl-whatsnew.md)