Please read the FAQ section before posting. The most common contact reason is why the app cannot be installed on devices prior to the iPhone 5S and iPad Air. If your device does not have an Apple A7 processor or better, then it will not support the Metal API technology used to render the simulated ZX81 display. Hence, the App Store app will prevent it from installing on the fourth generation iPad, the iPhone 5(c) and prior devices.
We do not intend to develop a version to work on earlier devices. This is not a question of 32bit vs 64bit performance. Instead we prefer to focus development time on adding more functionality with the latest technologies that stay firmly on the technology road map of Apple.
We do not intend to develop a version to work on earlier devices. This is not a question of 32bit vs 64bit performance. Instead we prefer to focus development time on adding more functionality with the latest technologies that stay firmly on the technology road map of Apple.