MuseScore in Microsoft Store is outdated, still at 3.3.4
The MuseScore version in the Microsoft Store is still on version 3.3.4
Windows 10 users of the "S" version (School?) can install only from the Microsoft Store, so are cut off of updates currently and since quite a while.
Getting that version updsated has been promissed since quote a while, yet it has not happened so far.
It might (not sure) be possible to use the PortableApp (furtunately availavle since 3.5, see #309861: MuseScore 3.5 is not available on the PortableApps.com site & Platform application), as a workaround