The store has been online for almost 3 weeks now, and I've been asked several times whether the Novation Circuit Editor also runs on older iPads.
I'm testing the editor on 2 different models: A 2021 IPad Pro (12.9 inch) and an old Ipad Air 2, which is almost 10 years old. The only measurable difference is that the editor takes 1 second to start on the new iPad, while the old one takes 2 seconds. That's it. Really, the editor runs reliably and flawlessly on the old hardware (yes, ok, it feels a tad smoother on the Pro, but maybe that's just what my brain wants because it was so expensive :-))
The screen size makes a bigger difference. It's particularly comfortable to work on the large display, but editing is also easy on a normal (10.9) iPad. I haven't tested an iPad Mini yet, but I imagine editing is much more fiddly here. I would rather tend to go for an older used iPad with a normal-sized screen.
(And of course the same applies all the more to the IPhone.)