With the switch from 0.83 to 0.9, I thought it would maybe be a good idea to convert all my file tags to id3v2. I assumed, it would be as simple as highlighting all my files and pressing the "rewrite file tags" button. What happened now, is that most of the tags were in fact rewritten, but some of the tags were just deleted (my %trackrating% tags, and %last_played%" etc.). Luckily I had a backup, but now I am back at the starting point. What would be the best way to update my tags without losing anything ?

IMHO id3v2 could be improved in 0.9
look here.