I am on 1.7 and it works well. We were moving from 1.7 to 1.9 on a new server. I had the 1.9 working as a brand new empty version, but when I tried to restore the 1.7 h2 data, it failed and wiped my users (so I could not log in). I reset the first time flag and was able to start fresh, but even if I try to restore from the first time screens, it fails. I can't figure out how to post the error file, but it looks like it trying to create empty records in user and failing. (user_id cannot be NULL).