You are reminded that version 2.3 is currently still in beta. That means that this version is not stable yet. Bugs and problems are expected to crop up. If you so wished to upgrade and try out the new features, remember to:
- backup your data nightly
- check for latest updates and/or bug reports on the wp-testers mailing list
- report any bugs or problems found while using
Finally, you can download WordPress 2.3 Beta 1 here.