MuseScore 3.6.2 is available for and fully compatible with Windows 11.
The message you are seeing has nothing to do with Windows 10 vs 11. The current version of MuseScore – 3.6.2 – runs equally well on both systems. If you are seeing a message about a score being created with an older version, it means, something a version of MuseScore older than 3.6. You’d see the same message trying to open on 3.6.2 on Windows 10 or on Windows 11.
If you aren’t using 3.6.2 on your new system, you should install it. The way to do that is from this website – see the Download menu above. I’m guessing you installed from the Microsoft store, but that tends to only have older versions. Remove that then download and install 3.6.2 from this site.
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