OS development using Xcode 7 are also covered, including Swift playgrounds, universal user interface design using size classes, app extensions, Interface Builder Live Views, embedded frameworks, Cloud. Kit data storage and Touch. ID authentication. The key new features of i. OS 9 and Xcode 7 are also covered in detail, including new error handling in Swift 2, designing Stack View based user interfaces, multiple storyboard support, i. Pad multitasking, map flyover support, 3. D Touch and Picture in Picture media playback.