There's still a lot of stuff to do. If anyone wants to help, you are mostly welcome!

• Error handling when creating a folder with invalid characters etc.
• Header match rule: user can put a custom header to matched against (editable box instead of Select).
• Folder creation does not work while editing an existing rule.
• Support advanced mode, so that the user can edit the SIEVE scripts directly (if she knows SIEVE).
• (0.9.9) Support "ready-made rules", like: All messages sent only to me, Place emails alphabetically in folders A-M and N-Z, Spam Filter etc. (need ideas!)
• (1.1) In a message with List-ID: header, provide the option to automatically add a filtering rule for mailing list emails.
• Support TLS connects to timsieved, in sieve-php.lib.php.
• Support Sieve Extension: Relational Tests, the :count matchtype.
• Support Sieve - body extension (started partial implementation)
• Respond with mime-encoded files. Support the :mime parameter. (info-cyrus relevant mail)
• (2.0+) Support multiple SIEVE scripts.
• (2.0?) Synchronization between folders mentioned in fileinto rules and actual folders that exist in the Cyrus tree.
• (3.0+) Sort out the GUI when adding a new rule. Make it more dynamic and support mixed, complicated AND/OR logic.