The documentation regarding Acro mode states:
In the current implementation the controller won’t use rudder while the plane is on it’s side to hold pitch, which means horizontal rolls won’t be as smooth as a good manual pilot, but that should be fixed in a future release. This also means that it won’t hold knife-edge flight.
Is “won’t use rudder” still the case today?
If so, how hard is it to implement use of rudder for knife-edge flight?