Originally Posted by Kressenstein
Coming back to the original topic, I know for a fact that the replay incompatibility involves iPhone 5 as well as iPad 4 (which I own). So, for instance, if I want to see a replay from Nytmair, I download it on the iPad 4. If an older device is involved, I'll download it on my old iPad 2.
These newer devices seem to have a slightly different hardware structure (or something like that) that changes the overall physics of the game a tiny little bit. At least that's my theory.