Sylpheed-Claws 2.1.1 has been released today! It’s the first release out of the new stable branch. This means it’s 2.1.0 plus all the bugs fixed in CVS since this release, but without the new features in CVS. This way it should be really stable.

You can download it there, and the release notes are here.
I feel unmotivated for the packages right now, though ;)