We've discussed PHP version requirements for Elgg, but we haven't talked about MySQL server reqs. Currently our reqs only specify "MySQL 5+." We received a PR that uses features in MySQL 5.5.3, which was released in early 2010.

MySQL doesn't seem to use semver verision, so features are introduced in what we'd call bugfix releases.

I don't mind requiring a specific version of MySQL server, but I haven't done the research yet to see which would be best. Other thoughts?