Most business owners never think about how Windows Update works – it just does. But according to Microsoft, as reported by TechSpot, the certificates that Windows Update relies on have a built-in expiry date, and they have to be replaced for a PC to keep receiving its monthly updates.
The next expiry date is 19 June 2027. That sounds a long way off, but a PC that misses the replacement will stop getting security patches, and an unpatched PC is one of the easiest ways into a business network.
Which PCs need what
Here is what Microsoft has said, version by version:
- Windows 11 version 25H2 and later: already have the new certificates. Nothing extra to do.
- Windows 11 version 24H2 and Windows Server 2025: need the September 2025 security update or later installed before 19 June 2027.
- Other supported Windows 11 versions and Windows Server 2022: need the July 2026 security update or later, with the same deadline.
- Supported Windows 10 versions: also need the July 2026 update or later, with the same deadline.
What to do this month
The good news is that a PC which is actually installing its monthly updates should pick this up on its own. The risk is the PC that quietly stopped updating months ago – the laptop that is always “remind me later”, the reception PC nobody restarts, or the old server in the cupboard.
- Check each PC’s version. Press Windows + R, type winver and press Enter. It shows the version, such as 24H2 or 25H2.
- Check when it last updated. Go to Settings, then Windows Update, then Update history. If the latest entry is months old, something is wrong.
- Do not forget servers. Windows Server 2022 and 2025 are on the list too.
- Plan for anything older. A PC on a Windows version that is no longer supported is already missing patches, and this is one more reason to replace or upgrade it.
A quick check now costs a few minutes. Finding out next June that half the office stopped patching costs a lot more.
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