Microsoft ships Windows 10 KB5126657 extended security update
The October 2026 Patch Tuesday update bumps Windows 10 to build 19045.7807 and adds DST changes for British Columbia and Alberta.
Microsoft released the Windows 10 KB5126657 extended security update on October 13, 2026, according to BleepingComputer. The package carries the October 2026 Patch Tuesday fixes for the aging operating system.
After installing KB5126657, Windows 10 moves to build 19045.7807. Windows 10 Enterprise LTSC 2021 moves to build 19044.7807 with the same update.
The release also enables permanent Daylight Savings Time support for British Columbia and Alberta starting November 2026, and introduces the new time zone Manitoba Standard Time (UTC-5:00) Manitoba.
On the storage side, the update adds auditing and optional policy controls for ReFS volumes on externally attached storage devices. It addresses an issue that might cause some Storage Spaces Direct virtual disks to remain offline after installing a Windows update, and fixes an issue where File History might fail to back up or restore files to an external drive or network location.
Microsoft continues deployment of updated Secure Boot certificates with this update. The company no longer releases new features for Windows 10, which is why KB5126657 is distributed as an extended security update rather than a feature release.
Quick answers
What build does Windows 10 reach after KB5126657?
Windows 10 moves to build 19045.7807. Windows 10 Enterprise LTSC 2021 moves to build 19044.7807.
Does KB5126657 change any time zones?
Yes. It enables permanent Daylight Savings Time for British Columbia and Alberta starting November 2026 and adds the new Manitoba Standard Time (UTC-5:00) Manitoba time zone.