Yes, I tried this yesterday but it didn't work ... I closed MP3tag, made the changes and started once more but everything was modified, not only the year.
OK, I tried it but I have still the same result:
Discogs finds the album and updates the tracks from title/year/album everything but I don't understand that behaviour.
Now it works, after I restarted windows. There must be something in cache somewhere, because I tried it several times and than I changed the source name and made the reboot.
What do I have to do to accomplish such changes? I can't reboot every time.