This version adds support for UTF8-encoded frames in ID3V2.4.0 tags.
There are some other minor UI changes related to removing the "What's this" button from most windows (it wasn't used anyway) and adding maximize / minimize buttons on Windows (they still don't show up under Gnome / Metacity, though.)
Another Windows-only change is that if the main window was maximized when the program exited, it will be shown as maximized when the program is restarted. (I didn't test this on Vista, so it might not work there, but it shouldn't matter much.)
You can download MP3 Diags 0.99.02.012 here.