I run Windoze under Virtualbox. I upgraded my Win10 instance to Win11 a while ago. It was 21h2 I believe. I also installed ExplorerPatcher so it looks like Win10.
A couple of months ago I started getting this notice that my Windoze was about to go out of support. Found out that update wasn't installing new service packs. So I got a Win11 24h2 DVD and upgraded it.
It flagged ExplorerPatcher as malware and had to uninstall it before the upgrade would run. Guess Micro$oft wants your Win11 to look like Win11 no ifs, ands or buts...