Drupal 7 has been released today. Among the new features are a redone administrative interface, speed optimizations, improved image handling, increased customization, and more.
A major security enhancement has been made, in previous versions user passwords were stored as unsalted MD5 hashes. The MD5 algorithm is “considered cryptographically broken” and salting passwords is necessary to limit the ability of passwords to be recorved through the use of rainbow tables. The new version stores new passwords in SHA-512 with a site-side hash, for passwords created in a previous version of Drupal the next time the a user successfully logs in the existing password hash will be replaced with the new version..
The new release increases the system requirements. You now need at least version 5.2.4 of PHP, version 5.0.15 of MySQL or version 8.3 of PostgreSQL. Support for SQLite 3.x has been added in the new version.
With the release of Drupal 7, support has ended for Drupal 5 as Drupal provides support for the two most recent major releases.