This is not about filtering new and fresh incoming mails.
It is about old mails stored in my inbox (pop3 or imap shoul not matter here) for weeks.
I want that mails moved automaticly to another folder when they reach a age.
In ClawsMail you can setup such rules folder specific. Everytime the folder lose its focus or Claws is closed that rules are executed. Very nice to organize the mails.
Can Thunderbird offer something like that, too?