A big one: no more "Easy Passwords 1.x compatible password" here, weaker password generation is gone for good. If you still had any legacy passwords these will be converted to stored passwords now, same happens when importing backups with legacy passwords.
The visible change: sync should now work with any server supporting remoteStorage protocol (https://remotestorage.io/). The bigger but rather hidden change: sync protocol requires even less trust in the storage provider now, no tampering with the data should succeed.
Oh, and did I mention keyboard navigation being more convenient and working far more consistently now?
Full list of changes: https://pfp.works/release-notes/2.2.0/
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