If your mail server doesn't support Sieve, Tiki will handle the filtering. Just add a command to Tiki Scheduler or a cron job:
php console.php sieve:filters
Exceptions:
Only available in Sieve
Redirects (like a forward except that email is modified so replies go to the original sender)
Better in Sieve
Blocked sender bounce: When done via Sieve, it is done when the email delivery is attempted. So the mail server is instructed not to accept the email, which is way better than accepting, and then replying with a rejection message. Ref: http://www.dontbouncespam.org/#BVR
Only available in Tiki
Functionality not covered by the Sieve standard. Here more and more features will be added like move an email to a tracker item via Email folders Tracker Field
Future plans
We will leverage Machine Learning so Tiki learns how you filter your emails manually.