Drupal 7.11 and 6.23, maintenance releases which fix security vulnerabilities are now available for download.Drupal 7.12 and 6.24 also fix other issues reported through the bug tracking system.
Upgrading your existing Drupal 7 and 6 sites is strongly recommended. There are no new features in these releases. For more information about the Drupal 7.x release series, consult the Drupal 7.0 release announcement, more information on the 6.x releases can be found in the Drupal 6.0 release announcement. Drupal 5 is no longer maintained, upgrading to Drupal 6 is recommended.