If you’re using the iPad 4 (I think that’s the retina model), unfortunately IF no longer supports your device. Your device is still 32bit and in order to progress and continue, IF requires a 64bit device. Sorry!
This is an issue on Apple’s end showing the wrong error message.
The problem is that your device does not support OpenGL ES 3.0, a requirement for the new graphics in the latest update. Instead of saying this, however, Apple incorrectly states that it is to do with the version of iOS required.