Microsoft is replacing certificates that Windows PCs use to confirm they are talking to genuine Windows Update servers. Machines that miss the changeover will stop receiving updates. The current certificates expire on May 17 and June 19, 2027. Most users won't have to do anything since the replacements ship inside regular monthly security updates.
Windows 11 25H2 and later, including 26H2, need no action. Windows 11 24H2 needs the September 2025 security update or newer, while other supported Windows 11 and Windows 10 versions need the July 2026 update or later before June 19. Windows 10 Enterprise 2019 LTSC, Windows Server 2019, and Windows Server 2016 face the earlier May 17 deadline.
Microsoft says devices on unsupported versions will lose access to Windows Update services. For home users, this affects Windows 10 PCs never enrolled in Extended Security Updates (ESU) after the OS reached end of life in October 2025. Microsoft extended ESU coverage to October 12, 2027.
Source: TechPowerUp News · Summarized by HeadlinesBriefing