Today, we're proud to announce the first beta version of Drupal 7.x for your further testing and feedback!
The jump between alpha to beta means the following:
* We think that we have resolved all critical data loss and security bugs in Drupal 7.
* We think that our APIs are now frozen enough so that contributed module and theme authors can start (or pick up again) their #D7CX pledges.
* We think that we have caught and fixed most of the problems with the upgrade path. We were able to successfully upgrade a copy of the Drupal.org database to Drupal 7.
That said, we definitely still have some bugs to shake out, and we need your help to find them! Especially new folks who haven't taken Drupal 7 for a spin yet. So please, do so, and let us know what bugs you find in the "Drupal core" issue queue (Please search incoming issues before filing).
Tons of stuff! A revamped user interface, a new admin and default core theme, image handling in core, fields (CCK!) in core, module and theme upgrades from within the browser, an automated testing framework with over 24,000 tests, improved security and scalability, revamped database, AJAX, and file systems, jQuery 1.4, jQuery UI 1.8, RDFa, and literally gazillions of other things! Please see CHANGELOG.txt for a comprehensive list of all improvements in Drupal 7.