https://www.bleepingcomputer.com/news/microsoft/windows-10-kb5005565-and-kb5005566-cumulative-updates-released/

The September 2021 Patch Update is released and Microsoft is now rolling out new KB5005565 and KB5005566 cumulative updates for recent versions of Windows 10.

Today's cumulative updates include security fixes for PCs with May 2021 Update (version 21H1), October 2020 Update (version 20H2), and May 2020 Update (version 2004).