Windows 10 KB5078885 ESU out with Secure Boot 2023, replacing expiring Secure Boot certificates from 2011. But it's a staged roll out.

How to check your Windows PC for expiring security certificates - a big one is ending soon ...

Microsoft confirms systems without updated Secure Boot certificates will boot normally but lose some security protections.

Windows 10 and Windows 11 rely on three security certificates that begin expiring from June 2026, with additional expirations later in 2026. Microsoft is treating this as a broad, ecosystem-level ...

In June 2025, Microsoft announced that, in June 2026, it would begin deprecating Secure Boot certificates of Windows systems from 2011, which were superseded by their 2023 counterparts.