Microsoft has warned that Windows devices running unsupported versions, or missing recent updates, will lose access to Windows Update when its certificates are rotated in 2027.

• What it is: Windows Update certificates expire on 17 May 2027 and 19 June 2027. Replacement certificates are already being delivered to supported, up-to-date systems.
• Who is affected: Any device on an unsupported version of Windows, or one that has not installed the required updates in time.
• The risk: Affected devices will receive no updates of any kind, leaving them exposed to new threats.
• What to do: Windows 11 25H2 and later need no action. Windows 11 24H2 and Server 2025 need the September 2025 update or later. Other supported Windows 11, Windows 10 and Server 2022 need the July 2026 update or later, before 19 June 2027. Server 2019, Server 2016 and Windows 10 Enterprise 2019 LTSC need the July 2026 update or later before 17 May 2027.

We recommend businesses identify older machines now and plan upgrades well before the deadlines. OzComm can audit your fleet on request.

Sources: BleepingComputer