Microsoft Windows 11 26H1 Update Version OS Build 28000.2704
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Update Summary
KB5121000 for Windows 11, version 26H1 updates OS Build 28000.2704 with the latest security fixes and non-security improvements from prior releases. It also references the August 2026 Security Updates guide and includes servicing stack update KB5121292.
Update Details
Security
- Includes the latest security fixes and addresses security vulnerabilities documented in the August 2026 Security Updates guide.
- Improves Secure Boot certificate targeting data to expand coverage for devices eligible to automatically receive new Secure Boot certificates.
Bug Fixes
- Improves TPM maintenance reporting so EK certificate status is reported accurately.
- Includes non-security updates carried forward from KB5101649 and KB5101681.
Known Issues
- Microsoft is not currently aware of any issues with this update.
Hints
- If previous updates are already installed, only the new updates in this package will be downloaded and installed.
- Includes servicing stack update KB5121292 (Build 28000.2602), which improves the reliability of the Windows Update installation process.
- AI components are updated to version 1.2605.856.0 for Image Search, Content Extraction, Semantic Analysis, and Settings Model.
Product Information
Vendor: Microsoft
Product: Windows 11
Product type: Software
Application category: Utilities
Platform: Windows
Variant: 26H1
Version: OS Build 28000.2704
Vendor release date: Aug 11, 2026
Original release notes: View on vendor site
Published on updatealert.io: Aug 12, 2026
Description: Client operating system for modern desktop and enterprise environments.