- Some security hardening to media uploads
- Performance improvements
- Fixes for IIS6 support
- Fixes for taxonomy and PATHINFO (/index.php/) permalinks
- Fixes for various query and taxonomy edge cases that caused some plugin compatibility issues.
The first hardens CSRF prevention in the media uploader. The second avoids a PHP crash in certain environments when handling devilishly devised links in comments, and the third addresses an XSS flaw.