April 9, 2025—KB5055547 (OS Build 10240.20979) - EXPIRED
Applies To
Release Date:
8/4/2025
Version:
OS Build 10240.20979
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EXPIRATION NOTICE IMPORTANT As of January 27, 2026, this update is no longer available from the Microsoft Update Catalog or other release channels. We recommend that you update your devices to the latest version of Windows. |
Support for Windows 10 has ended on October 14, 2025
After October 14, 2025, Microsoft will no longer provide free software updates from Windows Update, technical assistance, or security fixes for Windows 10. Your PC will still work, but we recommend moving to Windows 11.​​​​​​​​​​​​​​​​​​​​​
For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. For an overview of Windows 10, version 1507, see its update history page.
Important Windows updates do not install Microsoft Store application updates. If you are an enterprise user, see Microsoft Store apps - Configuration Manager. If you are a consumer user, see Get updates for apps and games in Microsoft Store.
Summary
This cumulative update for Windows 10, version 1507 contains security and quality improvements. The following is a summary of the key issues that this update addresses. The bold text within the brackets indicates the item or area of the change we are documenting.
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This update addresses security issues for your Windows operating system.
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[Daylight Saving Time (DST)] Update for the Aysen region in Chile to support the government DST change order in 2025. For more information about DST changes, see the Daylight Saving Time & Time Zone Blog.
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[OS Security] After installing this update or a later Windows update, a new %systemdrive%\inetpub folder will be created on your device. This folder should not be deleted regardless of whether Internet Information Services (IIS) is enabled on the target device. This behavior is part of changes that increase protection and does not require any action from IT admins and end users. For more information, see CVE-2025-21204.
If you installed earlier updates, only the new updates contained in this package will be downloaded and installed on your device.
For more information about security vulnerabilities, please refer to the new Security Update Guide website and the April 2025 Security Updates.
Known issues in this update
Microsoft is not currently aware of any issues with this update.
How to get this update
EXPIRATION NOTICE
IMPORTANT As of January 27, 2026, this update is no longer available from the Microsoft Update Catalog or other release channels. We recommend that you update your devices to the latest version of Windows.​​​​​​​
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