I'm not sure if this is the correct forum, but here goes. I have the Roundcube plugin and it's working well. I am able to create filtering on To, From, and Subject. That being said I would love the ability to create a filter on CC as well. Many mailing lists reply to the user and CC the list. Is that possible with the plugin, or do I need to do something else? It would be great if my users could create their own CC filters as well.
If you're using dovecot a different solution would be to setup the managesieve daemon and use roundcube's sieve plugin for filtering, it's quite flexible.