Just like all the previous builds you cannot mix and match versions so all your iPads will need to updated to 3.0 so if you need to still use an iPad, they will all need to stay on Master Fader 2.1.1.
Also of note when Master Fader 3.0 is released this week, My Fader 3.0 is not ready for release and My Fader 2.0 will NOT work with Master Fader 3.0. So if you need to continue to use My Fader on an iPhone or iPod touch, you'll want to not upgrade and stick with Master Fader 2.1.1 a little longer. Sorry for the inconvenience.