Software differences beetween iPad 2, iPad Air and iPad mini (iBooks)
I don't believe there are any software differences at all between an iPad mini and an iPad 2 or iPad Air. Both iPad minis use the exact same display resolution as their larger counterparts (1024x768 non-retina, 2048x1536 retina), just on a physically smaller screen. The whole purpose of this is to ensure that all existing software works identically on both device sizes.

In fact, I don't think it's even possible for an app to "know" which size device it's running on, since there's no technical way to differentiate them. Apple's own iOS Simulator doesn't even list the iPad mini as a separate device to simulate: the only options are iPad (meaning 1024x768) and iPad Retina (meaning 2048x1536).