iPhone 4, Original iPad support ended 2014
Before you buy: the RÃ˜DE Rec software requires iOS 8.1 at lowest.
So this old i-XY model can work as designed on iPhone 4S, or iPad 2 or 3 (24-bit/96K recording , 72Hz roll-off, headphones port pass-through).
If your RÃ˜DE Rec installation is old enough, this should work as well as it always did, which is: great value for money. Just deal with the quirks don't expect the world.
You *might* be able to make this happen on newer Apple hardware with a Lighting-to-30-pin adapter. You'd better do complete homework on that, unless gambling is your thing. I have not tried and don't want to.