Release Notes

    Couchbase Sync Gateway
    This content describes the key features and changes implemented by release 4.1 of Couchbase Sync Gateway

    One Way Upgrade

    The migration to a 4.x configuration is a ONE WAY process — see: Upgrading for more.

    4.1.1 — July 2026

    If you use Sync Gateway 4.1.0, upgrade to this release to receive critical fixes.

    Enhancements

    None for this release.

    Known Issues

    None for this release.

    Deprecations

    None for this release.

    4.1.0 — June 2026

    Users of this release should upgrade to Sync Gateway 4.1.1 or later to receive critical fixes.

    Version 4.1.0 of Sync Gateway delivers the following features and enhancements.

    Non-Disruptive Rolling Upgrades

    Sync Gateway 4.1 introduces cluster compatibility version, enabling node-by-node upgrades without downtime, with a safe rollback path throughout the upgrade window.

    For more information, see Cluster Compatibility Version.

    Distributed Resync

    Sync Gateway 4.1 redesigns resync to distribute work in parallel across all cluster nodes, replacing the previous single-node sequential approach.

    For more information, see Resync.

    Channel History Management

    Sync Gateway 4.1 introduces Admin REST API endpoints for retrieving and pruning channel history on both user records and documents, reducing metadata bloat and unnecessary revocation messages during zero-checkpoint replications.

    For more information, see Channel History Management.

    Metadata Isolation: Migrate to System Collection

    Sync Gateway 4.1 introduces an opt-in migration that moves Sync Gateway internal metadata from _default._default to _system._mobile, isolating it from user application data. The migration is never applied automatically at upgrade and cannot be reversed.

    For more information, see Migrate Metadata to System Collection.

    For a full overview of new features in this release, see New in 4.1.

    Known Issues

    None for this release.

    Deprecations

    None for this release.

    Upgrading

    For more on upgrading — see: Upgrading