Windows 10 · 21H2 · Release · Security update (Patch Tuesday)

Feature update to Windows 10, version 21H2 (19044.7807)

Windows 10 21H2: Servicing ended

Microsoft release information · Verified Oct 13, 2026

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AI summary

Released October 13, 2026, KB5126657 is the Windows 10 version 21H2 (OS build 19044.7807) security update for eligible ESU devices. It adds time-zone and ReFS security controls and fixes issues affecting Storage Spaces Direct and File History.

Generated from the package's release notes and forum coverage. Verify against Microsoft's release-health page before acting on it.

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