This iPhone 11, 11 Pro & 11 Pro Max (3 in 1) User Manual fully provides a solution to every difficult operational problem through do-it-yourself step by step latest tips, hint, and tactics; and also backed-up with many clear pictures and important screenshots that will make the uses of your iPhone 11 or iPhone 11 Pro or iPhone 11 Pro Max simple as ABC... in solving problems. There are a lot more tips on how you could upgrade old iOS version to latest compatible iOS version on your old iPhone 4, 4S, 5, 5C, 5S, 6, 6 Plus, 6S, 6S Plus, SE, 7, 7 Plus, 8, 8 Plus, X, XR, XS, or XS Max. Especially iOS 13 for second-generation iPhones.