--- title: Couchbase Lite Release Notes description: Couchbase Lite on C#.Net pubDate: 2026-08-17T09:53:44.266Z antora: editUrl: https://github.com/couchbase/docs-couchbase-lite/edit/release/4.0/modules/csharp/pages/releasenotes.adoc xref: xref:4.0@couchbase-lite:csharp:releasenotes.adoc[] --- [Consult the llms.txt file for a full list of contents](/llms.txt) [View original HTML](/couchbase-lite/4.0/csharp/releasenotes.html) # Couchbase Lite Release Notes Unresolved include directive in modules/csharp/pages/releasenotes.adoc - include::partial$release-notes/couchbase-mobile-csharp-release-note.4.0.4.adoc\[\] ## [](#maint-4-0-3)4.0.3 — February 2026 Version 4.0.3 for C#.Net delivers the following features and enhancements: ### [](#enhancements)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) ### [](#fixed-issues)Fixed Issues * [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)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-4-0-2)4.0.2 — December 2025 Version 4.0.2 for C#.Net delivers the following features and enhancements: ### [](#enhancements-2)Enhancements None for this release ### [](#fixed-issues-2)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) * [CBL-7731 — WinUI has no console logging implementation registered](https://jira.issues.couchbase.com/browse/CBL-7731) ### [](#known-issues-2)Known Issues None for this release ### [](#breaking-changes)Breaking Changes 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-4-0-0)4.0.0 — November 2025 Version 4.0.0 for C#.Net delivers the following features and enhancements: ### [](#enhancements-3)Enhancements * [CBL-5368 — Support Proxy Authenticator API for .NET Android](https://jira.issues.couchbase.com/browse/CBL-5368) * [CBL-6569 — Disabled SQLite's mmap by default](https://jira.issues.couchbase.com/browse/CBL-6569) * [CBL-7281 — Support timestamp property in Document](https://jira.issues.couchbase.com/browse/CBL-7281) * [CBL-7285 — Support Last-Write-Win as the default conflict resolution algorithm for Replicator](https://jira.issues.couchbase.com/browse/CBL-7285) * [CBL-7330 — Add API for creating ReplicatorConfiguration with collection configs and endpoint](https://jira.issues.couchbase.com/browse/CBL-7330) * [CBL-7416 — Update Database APIs to Return or Throw NotOpen Error for Closed Database Cases](https://jira.issues.couchbase.com/browse/CBL-7416) * [CBL-7568 — New Version Vector Database](https://jira.issues.couchbase.com/browse/CBL-7568) ### [](#fixed-issues-3)Fixed Issues * [CBL-6482 — Unpackaged apps on net8.0-windows cannot create databases](https://jira.issues.couchbase.com/browse/CBL-6482) * [CBL-6504 — Query parser regression related to brackets](https://jira.issues.couchbase.com/browse/CBL-6504) * [CBL-6513 — Race creating the expiration column in a collection table](https://jira.issues.couchbase.com/browse/CBL-6513) * [CBL-6798 — Release c4log\_getDomain C# string bytes](https://jira.issues.couchbase.com/browse/CBL-6798) * [CBL-7413 — FWrong error shown when using mismatch collections in Replicator](https://jira.issues.couchbase.com/browse/CBL-7413) ### [](#known-issues-3)Known Issues * [CBL-7572 — Database.Copy() doesn't convert Self-Source-ID to the original Source ID](https://jira.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://jira.issues.couchbase.com/browse/CBL-7573) ### [](#breaking-changes-2)Breaking Changes * [CBL-1946 — Enhanced .NET Configuration API with Init-Only and Required Properties](https://jira.issues.couchbase.com/browse/CBL-1946) * [CBL-6596 — Vector Search Extension 2.0.0 Required for Couchbase Lite 4.0.0](https://jira.issues.couchbase.com/browse/CBL-6596) * [CBL-7290 — Removed : Deprecated Database APIs](https://jira.issues.couchbase.com/browse/CBL-7290) * [CBL-7294 — Removed : Deprecated Remove Change Listener APIs](https://jira.issues.couchbase.com/browse/CBL-7294) * [CBL-7298 — Removed : Deprecated QueryBuilder APIs](https://jira.issues.couchbase.com/browse/CBL-7298) * [CBL-7302 — Removed : Collection Management API from ReplicatorConfiguration](https://jira.issues.couchbase.com/browse/CBL-7302) * [CBL-7341 — Removed : CollectionConfiguration's constructor without collection](https://jira.issues.couchbase.com/browse/CBL-7341) * [CBL-7342 — Removed : ReplicatorConfiguration API for managing collection configurations](https://jira.issues.couchbase.com/browse/CBL-7342) * [CBL-7343 — Removed : ReplicatorConfiguration's constructor with a target endpoint only](https://jira.issues.couchbase.com/browse/CBL-7343) * [CBL-7380 — Removed : DatabaseConfiguration's mmapEnabled property](https://jira.issues.couchbase.com/browse/CBL-7380) * [CBL-7392 — Removed : Deprecated Default Constants](https://jira.issues.couchbase.com/browse/CBL-7392) * [CBL-7570 — Removed : Deprecated Replicator and Listener API](https://jira.issues.couchbase.com/browse/CBL-7570) ### [](#deprecations-3)Deprecations * [CBL-7306 — Deprecate TLSIdentity.createIdentity() with isServer boolean flag](https://jira.issues.couchbase.com/browse/CBL-7306) > [!NOTE] > For an overview of the latest features offered in Couchbase Lite 4.0, see [New in 4.0](../cbl-whatsnew.md)