Drupal 6.17 is now available for download.

This is a maintenance release, which improves compatibility with PostgreSQL, PHP 5.3 and PHP 4. The CSS and JS aggregation has also undergone a compatibility update. An incompatibility of Drupal 6.16's new lock subsystem with some contributed modules has also been resolved, and Drupal 6.17 has changed the way it handles session cookies.

Please see the announcement for more information.