That’s right, two shiny new bugfix/security updates. One for the 2.0 branch and one for the 2.1 branch. There are some small bugfixes in both of these versions, but the main reason to upgrade is for the security fixes (I’m going to write more on that subject later).
Watch later this month for the release of WordPress 2.2. This upcoming release will add several new features, including built-in support for tags(!), Atom 1.0 feeds for posts and comments, some preliminary Atom Publishing Protocol support (I’ve been working on that), several new XML-RPC methods, widget support in the default templates, performance enhancements, and several other things that I can’t think of right now. Obviously, there will be more details available at the time of the official release, which is slated for April 22.