by Mark Pearson.
I've had few problems with restoring 1.9 course backups into moodle version 2.3 or 2.4. No, you cannot bring over course enrollments or grades but then why would you want to do that anyway? I maintain a running 1.9 that faculty can access at a different URL so that they can check old grades etc. In fact, I've had fewer problems with the version 2 backup/restore than before -- it's amazingly flexible, predictable and rock solid. For example, someone accidently deleted an assignment from a course; I was able to backup just that assignment from a different moodle 2 system and restore it with disturbing anything else. Brilliant!