Following on the third beta release two weeks ago, we are ready to present Drupal 6.0 beta 4. Since the previous beta release, we have committed over 80 fixes to the Drupal 6.x code. This beta version includes some usability improvements and lots of bug fixes for issues which the testers and contributed module upgraders encountered. The first beta announcement provided a comprehensive list of high level improvements made since Drupal 5.x, so in this announcement we'll concentrate on how you can help ensure that Drupal 6 is released as soon as possible and is as rock solid as the previous Drupal releases that you've grown to love!
Changes made since the release of Drupal 6.0 beta 3 include several multilingual support fixes, caching improvements, more clear help texts, drag and drop support for book outlines, user profile administration, taxonomy pages and file uploads, and fixes to node teaser generation. With the right to left version of the pushbutton theme, we also completed RTL support for all core themes. We have also hardened the security of the system, closing potential cross site scripting (XSS) and cross site request forgery (CSRF) security holes. This beta release also includes the security updates released in Drupal 5.4 and 4.7.9.
http://drupal.org/drupal-6.0-beta4