Release Candidate 2 of WordPress 2.2 is up.
Here is the full diff between RC1 and RC2.
And here’s the lowdown on what went into in RC2.
- The WP importer was reworked to get around a preg_match_all() problem in PHP 5.2.2. #4239
- The show count option for the archives widget now works for dropdowns. 
- TinyMCE is now enabled for Safari Webkit 420 and above. #4241
- A JS fix for Widgets admin. #5436
- Fix blogroll importing from local file. #4243
- Workaround a PHP 5.2.2 bug that was breaking XMLRPC. #4248
- An i18n fix for the akismet widget. #653
- Akismet also got some attribute escaping fixes.
- Eliminated duplicate code in get_posts(). #4251
- Return the proper server protocol when HTTP/1.0 is requested. #3886
- Flush all output buffers during shutdown to avoid problems with PHP 5. Should fix plugins that use output buffers. #3354