Microsoft has released cumulative update KB5124162 (Build 28120.3122) for Windows 11, version 26H1 for Insiders in the Experimental channel.
Update KB5124162 includes a small set of general improvements and fixes that make the system more stable. Microsoft did not list individual items in the build notes. The changes are rolling out to Insiders gradually, so they will not appear for everyone at the same time.
Notes for Insiders in the Experimental channel (26H1):
These builds may be unstable and are released with limited documentation.
Builds released to the Experimental channel (26H1) represent the latest platform changes at early stages of development and are not tied to any specific Windows release. Features and capabilities included in these builds may never ship in a final version, as Microsoft is trying various concepts and gathering feedback. Features may change, be removed, or be replaced, and some of them may never become available outside the Windows Insider program. However, when these features are ready, they may appear in future Windows releases.
Many features in the Experimental channel (26H1) are rolling out using Controlled Feature Rollout technology. First they become available to a small group of Insiders, and then their availability expands as feedback is received and analyzed to assess how they are perceived before becoming available to all participants of this channel.
Desktop watermark: the presence of a watermark in the lower right corner of the desktop is normal for Windows Insider preview builds.
Some features that are in active development and that Microsoft previews to Insiders may not be fully localized. Localization will be completed as features are finalized. If you notice localization issues in your language, report them through the Feedback Hub app.
Installing via Windows Update:
Go to Settings > Windows Update and click Check for updates. A restart of the computer will be required to complete the installation.
Official announcement on the Microsoft website.
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5124166 | 26220.9568 | 25H2 | Windows 11 | Beta | 2026-09-25 |
| KB5124163 | 28020.3112 | 26H1 | Windows 11 | Beta | 2026-09-25 |
| KB5124162 | 28120.3122 | 26H1 | Windows 11 | Experimental | 2026-09-25 |
| KB5124165 | 26340.9577 | 26H2 | Windows 11 | Experimental | 2026-09-25 |
| KB5124006 | 28000.3086 | 26H1 | Windows 11 | Preview | 2026-09-22 |
| KB5124010 | 26200.9550 | 26H2 | Windows 11 | Preview | 2026-09-22 |
| KB5124138 | 28120.3032 | 26H1 | Windows 11 | Experimental | 2026-09-18 |
| KB5124140 | 26220.9492 | 25H2 | Windows 11 | Beta | 2026-09-18 |
| KB5124137 | 26340.9502 | 26H2 | Windows 11 | Experimental | 2026-09-18 |
| KB5129242 | 22631.7584 | 23H2 | Windows 11 | Stable | 2026-09-14 |