We just announced RC1 on the dev blog. The only change since Beta 1 was a small fix to wp-mail.php to address ticket #5169. If there are no unpleasant surprises, the final 2.3.1 release should be out in the next day or two.
- Tagging support for Windows Live Writer
- A login bug that affected those with a Blog Address different than
their WordPress Address is fixed
- Faster taxonomy database queries, especially tag intersection queries
- Link importer fixes
The standard disclaimer for beta software applies. Please report any bugs you find on the bug tracker.