Microsoft has released the Windows 11 KB5009566 cumulative update with security updates, performance improvements, and fixes for known bugs.

KB5009566 is a mandatory cumulative update as it contains the January 2022 Patch Tuesday security updates for vulnerabilities discovered in previous months.

Windows 11 users can install today's cumulative update by going to Start Settings > Windows Update and clicking on 'Check for Updates.' 

KB5009566 update offered in Windows Update

Windows 11 users can also manually download and install the KB5009566 update from the Microsoft Update Catalog.

What's new in the Windows 10 KB5009566 update

After installing the KB5009566 update, Windows 11 will change its build number to 22000.434.

For the past few months, Microsoft's cumulative update changelogs have not had a lot of information on what bugs were fixed. This could be due to the holidays, and we will hopefully see more detailed lists of fixes in the coming months.

Microsoft states that the only non-security fix is for a known issue with Japanese Input Method Editors (IME).

"Addresses a known issue that affects Japanese Input Method Editors (IME). When you use a Japanese IME to enter text, the text might appear out of order or the text cursor might move unexpectedly in apps that use the multibyte character set (MBCS)," reads the KB5009566 support bulletin.

"This issue affects the Microsoft Japanese IME and third-party Japanese IMEs."

Microsoft states that a known issue continues to affect Windows 11, causing image editing program not to render colors correctly on HDR displays.

"After installing Windows 11, some image editing programs might not render colors correctly on certain high dynamic range (HDR) displays. This is frequently observed with white colors, which could display in bright yellow or other colors.

This issue occurs when certain color-rendering Win32 APIs return unexpected information or errors under specific conditions. Not all color profile management programs are affected, and color profile options available in the Windows 11 Settings page, including Microsoft Color Control Panel, are expected to function correctly."

Finally, Microsoft updated the servicing stack to resolve bugs or issues preventing Windows Updates from properly installing future updates.

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