Microsoft Entra Connect Sync version v2.6.3.0 addresses an issue where auto-upgrade would halt synchronization.

What's Fixed

Microsoft addressed a known issue in Entra Connect Sync v2.5.190.0 and v2.6.1.0, where the Automatic Upgrades feature could stop Entra Connect Sync from synchronizing unexpectedly with the following error:

System.IO.FileLoadException: Could not load file or assembly 'System.Diagnostics.DiagnosticSource, Version=6.0.0.1' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

From Entra Connect Sync v2.6.3.0 onwards, auto-upgrade now detects modifications to the miiserver.exe.config and miisclient.exe.config configuration files and skips automatic upgrade on these installations.

If admins manually upgrade and previously modified these configuration files, based on earlier guidance to support Password Hash Synchronization (PHS) in FIPS enabled environments as a workaround, they might encounter installation failures.

Version information

Version 2.6.3.0 of Entra Connect Sync (previously known as Azure AD Connect Sync) was made available for download on March 10th, 2026.

Admins can download the latest version of Entra Connect Sync from the Entra admin center.

Superseded versions

Past versions of Microsoft Entra Connect Sync 2.x are retired 12 months from the date they are superseded by a newer version. With the release of Entra Connect Sync v2.6.3.0, support for Entra Connect Sync version 2.6.1.0 stops on March 10th, 2027.

Support for Entra Connect Sync v2.4.27.0 and earlier versions of Entra Connect Sync has already stopped.

If you run a retired version of Microsoft Entra Connect, it might unexpectedly stop working.