Windows 10 has firmly entered its long-term maintenance phase, with feature development now behind it and security taking center stage. For organisations and users enrolled in Microsoft’s paid Extended Security Updates (ESU) program, the January 2026 maintenance release arrives in the form of update KB5073724.
Microsoft published KB5073724 on January 13, 2026. The update raises Windows 10 version 22H2 to build 19045.6809, while Windows 10 21H2 and LTSC 2021 systems move to build 19044.6809. As with all ESU updates, the focus is strictly on security and system integrity rather than new functionality.
ESU-only update for post-support Windows 10
Windows 10 22H2 officially reached end of support on October 14, 2025. Since then, Microsoft has limited security fixes to customers who opted into the ESU program, which provides “critical and important” updates for a fee. KB5073724 is part of that paid lifecycle and will only be offered to devices properly licensed for ESU.
For administrators who prefer manual deployment, the update is also available through the Microsoft Update Catalog, bypassing the need to wait for Windows Update.
What’s included in KB5073724
While the change log is short, several points stand out:
- Driver removals: The update removes legacy modem drivers, including agrsm64/agrsm and smserl64/smserial. Systems that still rely on hardware using these drivers may lose functionality after installation.
- Secure Boot certificates: Microsoft warns that Secure Boot certificates used by many Windows devices will begin expiring from June 2026. KB5073724 initiates a gradual rollout to identify eligible systems and prepare them for updated certificates, helping to prevent future boot or security issues.
- WinSqlite3.dll update: The bundled WinSqlite3.dll component has been updated following a vulnerability flagging by certain security products. Microsoft clarified that this file is separate from the sqlite3.dll shipped with certain third-party applications.
Stability expected as Windows 10 winds down
Microsoft has not listed any known issues with this update. Given Windows 10’s maintenance-only status, significant regressions are considered unlikely, and updates are expected to remain narrowly scoped and conservative.
For organisations still running Windows 10 under ESU, KB5073724 is a reminder that while the operating system remains usable, the clock is ticking. Each monthly patch is now less about improvement and more about keeping ageing systems secure long enough to plan and execute a transition to newer platforms.
