This cumulative update for Windows 11, version 23H2 (KB5120240), includes the latest security fixes and improvements, along with non-security updates from last month’s optional preview release. Visit the Windows release health dashboard for the latest status on this release.
Want a quick overview? Watch the Windows 11, version 24H2 and version 25H2 video. |
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Announcements and messages
This section provides key notifications related to this release, including announcements, change logs, and end-of-support notices.
Windows Secure Boot certificate expiration
Important: Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. Microsoft has been updating these certificates on consumer and non-managed business devices over the past several months. Devices that haven’t received the newer certificates will continue to start and operate normally, and standard Windows updates will continue to install. Updated certificates will continue to be delivered through Windows Update in the coming months.
End of updates
Windows 11. Version 23H2 Enterprise and Education will reach end of updates on November 10, 2026. Devices running these editions will no longer receive fixes for known issues, time zone updates, technical support, or monthly security and preview updates containing protections from the latest security threats.
To stay protected and up to date, we recommend you upgrade to the latest version of Windows 11.
Improvements
This update addresses security issues for your Windows operating system.
Important
Use EKB KB5027397 to update to Windows 11, version 23H2.
This security update contains fixes and quality improvements from KB5099414 (released July 14, 2026). The following summary outlines key issues addressed by this update. Also, included are available new features. The bold text within the brackets indicates the item or area of the change.
- [Connectivity] This update refreshes the COSA profile for SolNet-Mobile to support the latest mobile operator settings.
- [Device Management] This update improves reliability for devices managed through mobile device management (MDM) by helping devices continue to perform normally when an MDM certificate expires.
- [File History] This update improves the reliability of File History backups to SMB network shares, helping scheduled backups access network locations and copy files as expected.
- [Secure Boot] This update includes additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Certificate deployment via Windows updates continues across supported PCs and non-managed business devices in the coming months.
- [Emoji Panel] The emoji panel (Windows key + period (.)) now supports GIPHY following the deprecation of Google's Tenor API.
If you've already installed previous updates, your device will download and install only the new updates included in this package.
For more information about security vulnerabilities, see the Security Update Guide and the August 2026 Security Update.
Windows 11 servicing stack update (KB5120239) - 22621.7513
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates. To learn more about SSUs, see Simplifying on-premises deployment of servicing stack updates.
Known issues in this update
Microsoft is not currently aware of any issues with this update.
How to get this update
Before you install this update
Microsoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates.
Deployment
If you deploy dynamic updates such as this update to an existing Windows image, ensure the boot.stl file is included as part of the installation media. Failure to include the file might prevent devices from successfully starting from the installation media and can result in error code 0xc0430001.
Note
The boot.stl file is used during Secure Boot validation and must match the Windows version and architecture of the image you are updating.
To ensure the boot.stl file is included as part of the installation media, do one of the following:
- Use the Update WinPE script to update an existing Windows image. (Recommended)
- Manually copy the boot.stl file from the device Windows\Boot\EFI folder to the corresponding folder on your installation media before deploying the update.
For information about how to apply Dynamic Update packages to existing Windows images, see Update Windows installation media with Dynamic Update.
Install this update
To install this update, use one of the following Windows and Microsoft release channels.
| Available | Next Step |
|---|---|
| ✅ | This update downloads and installs automatically from Windows Update and Microsoft Update. |
File information
For a list of the files provided in this update, download the file information for cumulative update KB5120240.
For a list of the files provided in the servicing stack update, download the file information for SSU KB5120239 - versions 22621.7513.
Related topics
Microsoft Store for Business and Education with Configuration Manager