I seem to remember sometime back reading that changing the appearance of the mail composer view controller was not allowed. However, I also just tried for the first time to implement changes to my navigation bars system wide using the
[[UINavigationBar appearance] setBackgroundImage
method
This changes the navigation bar in the mail composer view controller. So, is this now allowed to make changes? Reason I am doing the appearance call is I have a lot of navigation bars and would like to get them all set at once.
The appearance methods are documented and their effects are intended to be app-wide, so I see no reason why it would be a problem to use them.