KB5079490

Microsoft has released cumulative update KB5079490 (Build 28020.1797) for Windows 11 version 26H1, available to Insiders on the Canary channel.

Some changes being tested on this channel will never be released, while others may appear in future versions of Windows when they are ready.

Builds on the Canary channel do not correspond to a specific version of Windows, as this channel is intended for previewing the latest changes in the early stages of development, and experimental builds may be unstable due to being released immediately after creation with limited documentation.

• A small set of improvements and fixes. This update includes changes aimed at improving overall stability and system quality for Windows Insider Program participants using this build.
• Control Feature Rollout technology. Many features in the Canary channel initially become available to a small group of Insiders, then their availability expands as feedback is collected and analyzed.
• Lack of full localization. Some features under active development may not be fully localized; localization will be completed as features are finalized.

Known issues: leaving the Canary channel will require a clean installation of Windows 11, as Insiders cannot switch to a channel with lower build numbers without this. The presence of a watermark in the lower right corner of the desktop is normal for these preview builds. Some features may first appear in the Dev and Beta channels before appearing in the Canary channel.

Installation: go to Settings > Windows Update and click Check for updates, then a computer restart will be required. You can also manually download update KB5079490 and install it using the links above.

To update using an ISO image while keeping data and programs: join the Insider program via the OfflineInsiderEnroll tool, download the Windows 11 Insider Preview Build 28020.1797 ISO image, mount it (right-click -> Mount), run setup.exe, choose Keep files, settings, and applications, accept the terms and click Install. After updating, the build number will change to 28020.1797.

System stability and quality improvements: The update includes fixes in the kernel (ntoskrnl.exe) and critical drivers, addressing memory leaks and race conditions. This is achieved by backporting validated patches from stable branches, reducing the frequency of fatal exceptions (0x0000003B) and improving fault tolerance during the early boot cycle.

Control Feature Rollout (CFR): The technology uses server-side telemetry and FeatureConfiguration identifiers to activate code in stages. On Canary builds, flags default to 0 for most Insiders. When metrics show >95% successful module launches, the server sends a new masked DWORD via Windows Update, expanding the feature’s audience.

Partial localization of the interface: Features under development use string resources (.mui files) with a fallback mechanism. If the language pack (.dll.mun) for a region lacks a translation for a given resource, the Window Manager loads an en-US placeholder string (ID=0x03F2). Full localization is deployed via Language Pack Cab after API freeze.

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