Windows Server November updates fix Exchange instability and harden signing
🛠️ Microsoft released KB5131090 for Windows Server 2022 and KB5131080 for Windows Server 2025 on November 10. Both include fixes for on-premises Exchange access and mail-flow problems, Active Directory printer installation and Remote Desktop scenarios.
They also enable clients to offer NTLM signing by default for non-anonymous connections.
Windows PowerShell signature validation now checks encoding more strictly, so affected scripts may need valid UTF-8 with a byte-order mark and a new signature. The Server 2025 update additionally addresses certain in-place upgrade failures from Server 2016.
Microsoft continues to document the separate WSUS synchronization-error-detail limitation.
[Windows Server 2022 release notes](https://support.microsoft.com/en-us/servicing/os/windows-server/2026/11/kb5131090-windows-server-2022-security-update)
Partner briefing
- What it is
November 10 cumulative security updates are available for Windows Server 2022 and 2025.
- What’s changing
Exchange and administration fixes accompany NTLM-signing improvements and stricter Windows PowerShell encoding validation.
- Why it matters
Server maintenance includes application-compatibility fixes and script-signature behavior changes; the documented WSUS limitation persists.
- Who it affects
Administrators managing Windows Server 2022/2025, on-premises Exchange and Windows PowerShell automation.