The previous version 2.34 of the Windows Beta expired Jan 20. The Windows beta project format is incompatible with the version 1.16, which is why you’re seeing that message.
If you want to continue using the Windows beta (newest version is 2.35), you can download it from here: [url]Scrivener 3.0 Beta - Release Candidate 10 (Download Links & Change List)]
Best,
Jim