Hi,
When upgrading my single file wiki to 5.2.1 yesterday, I’ve found that the upgrader rejects my password-encrypted wikis. When attempting to upgrade, it did prompt for password, but nothing happened when I entered it.
To get around this, I had to clear the password from my wiki, save it as unencrypted, upgrade it in this way and then re-encrypt the upgraded version.
Just an FYI In case anyone else experienced this as there could be a bug in the upgrader.