MySQL Compatibility
MySQL 4.1
If you have schema importing errors (like "true is undefined"), upgrade to more recent version of 4.1 branch. I use 4.1.15 (Debian Sarge).
MySQL 5.0
My test machine runs 5.0.24a (Ubuntu Edgy) and seems to work fine except for database-backed sessions. Again, check for errors while importing schema.
See also: this forum thread