Microsoft has released cumulative update KB5120240 for Windows 11 version 23H2 (2023 Update) as part of the August 2026 Patch Tuesday. The system build increases to 22631.7517. Please note that support for Windows 11 version 23H2 in the Home and Pro editions ended on November 11, 2025, so these editions no longer receive monthly security updates automatically. Microsoft strongly recommends upgrading to Windows 11 version 25H2.
- Secure Boot. New data has been added for more accurate targeting of devices, which has increased the coverage of computers ready to automatically receive new Secure Boot certificates. In the coming months, their phased rollout through Windows Update will continue on supported PCs and unmanaged corporate devices.
- Connectivity. The COSA profile for the SolNet-Mobile operator has been updated — support for the latest mobile operator settings has been added.
- Device Management. The reliability of MDM-managed devices has been improved: they now continue to function normally even after the MDM certificate expires.
- File History. The reliability of File History backup to network folders via the SMB protocol has been enhanced. Scheduled tasks should now correctly access network locations and copy files.
- Emoji Panel. The emoji panel, invoked by the Win + . shortcut, now supports GIPHY. This change is related to the deprecation of the Google Tenor API.
Cumulative update KB5120240 installs automatically via Windows Update for Enterprise and Education editions. To check for the update manually, open Settings, go to the Windows Update section, and click Check for updates.
| Feature / Change | Performance Increase/Decrease | Optimization | PC Speed | Gaming Optimization |
|---|---|---|---|---|
| Secure Boot – new data for more accurate device targeting | 🟢 +2-5% Boot Time (fewer cert mismatches on startup) | 🟢 Medium – automatic certificate eligibility refinement | 🟢 Slight improvement (less authentication overhead during boot) | ⚪ No direct impact |
| Connectivity – updated COSA profile for SolNet-Mobile | ⚪ No measurable impact | 🟡 Low – carrier settings alignment | ⚪ No impact | ⚪ No impact |
| Device Management – MDM reliability after certificate expiry | 🟢 Prevents performance degradation on managed devices | 🟢 Medium – uninterrupted policy sync | 🟢 Prevents slowdown from failed MDM checks | ⚪ No impact |
| File History – enhanced SMB backup reliability | 🟢 +1-3% Network Copy Throughput (fewer retransmissions) | 🟢 Medium – scheduled task network access fixes | 🟡 Marginal (background task efficiency) | ⚪ No impact |
| Emoji Panel – GIPHY support replacing Google Tenor API | 🟡 Potential 50-100ms faster GIF loading (API latency change) | 🟡 Low – API backend swap | ⚪ No impact | ⚪ No impact |
Official announcement on the Microsoft website.
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5127757 | 28120.3181 | 26H1 | Windows 11 | Experimental | 2026-10-07 |
| KB5127758 | 26220.9606 | 25H2 | Windows 11 | Beta | 2026-10-07 |
| KB5127754 | 28020.3172 | 26H1 | Windows 11 | Beta | 2026-10-07 |
| KB5127753 | 26340.9616 | 26H2 | Windows 11 | Experimental | 2026-10-07 |
| KB5124192 | 28120.3151 | 26H1 | Windows 11 | Experimental | 2026-10-02 |
| KB5124196 | 28020.3142 | 26H1 | Windows 11 | Beta | 2026-10-02 |
| KB5124197 | 26220.9587 | 25H2 | Windows 11 | Beta | 2026-10-02 |
| KB5124193 | 26340.9596 | 26H2 | Windows 11 | Experimental | 2026-10-02 |
| KB5124166 | 26220.9568 | 25H2 | Windows 11 | Beta | 2026-09-25 |
| KB5124163 | 28020.3112 | 26H1 | Windows 11 | Beta | 2026-09-25 |