As usual, get it from the usual place, and follow the instructions if you’re upgrading from a previous version. I’ve just upgraded 11 blogs in about a minute (most of which was spent backing up the databases and the files, in case Something Bad ™ happened).

List of changes here.

Apparently, there’s a new problem when running on a server with FastCGI installed: it may give a 500 error in some cases. If that’s your situation, there’s a workaround.