Each version of Pressflow is API-compatible with the same major Drupal version. For example, Pressflow 6 is compatible with all Drupal 6 modules. Pressflow 6 also integrates the SimpleTest system from Drupal 7 and the CDN support patch.
Thanks to both Drupal's session handling when logging out (https://drupal.org/node/754560), and the session-free nature of Pressflow, there are several scenarios where a user does not see the message being saved by core:
User deletes their user account (via user_delete module).
User requests their password be reset.
Pressflow should extend core to provide logic that allows these user messages to be displayed.
Thanks to both Drupal's session handling when logging out (https://drupal.org/node/754560), and the session-free nature of Pressflow, there are several scenarios where a user does not see the message being saved by core:
Pressflow should extend core to provide logic that allows these user messages to be displayed.