The next versions of iOS and OS X are supposed to focus on performance and stability instead of new features, and that focus on performance could extend all the way back to devices that Apple released three and four years ago. According to 9to5Mac, a focus of iOS 9 has been optimizing the OS for old devices, including the iPhone 4S and iPad mini, neither of which handles iOS 8 very well. That’d be a change for Apple, which typically drops support for devices once they get that old. Apple is reported to have built a “core version” of iOS 9 that’s designed for these older devices. They will reportedly run that instead of receiving the OS as it’s optimized for Apple’s newest hardware.
reports The Verge