It’s not Mission: Impossible 4
Variety is claiming Paramount’s new Mission: Impossible film will not be called Mission: Impossible 4, but instead use a name much like how WB has handled the Batman franchise. The film is a reboot and will be treated as such, but seriously? Without that name, then it’s just another spy action film.
What’s next? No theme music? Jeremy Renner will co-star with Tom Cruise for the whatever-it-will-be-called for a December 2011 release.
Source: Collider

Mission: Improvement maybe?