Just upgraded from Lisa to Nadia; and things look great and work well. Except that I found I couldn't see whatever I typed into the Username/Password box during log-in - I guess because the font was white against a white background (partly-inherited desktop theme colours?). So I ran mdmsetup to get a different log-in theme; but that failed because /root/.local/share didn't exist. After creating that directory and re-running mdmsetup, all worked fine. Thought this might help other people irritated by the invisible typing during log-in. Also suggest to any developers reading this that the install script is modified to create /root/.local/share... Mint is still wonderful, though!