How to develop or migrate apps for iPhone 5 screen resolution?

Question

The new iPhone 5 display has a new aspect ratio and a new resolution (640 x 1136 pixels).

What is required to develop new or transition already existing applications

Answer 1

1. Download and install latest version of Xcode.
2. Set a Launch Screen File for your app (in the general tab of your target settings). This is how you get to use the full size of any screen, including iPad split view sizes in iOS 9.
3. Test your app, and hopefully do nothing else, since everything should work magically if you had set auto resizing masks properly, or used Auto Layout.
4. If you didn't, adjust your view layouts, preferably with Auto Layout.
5. If there is something you have to do for the larger screens specifically, then it looks like you have to check height of [[UIScreen mainScreen] bounds] as there seems to be no specific API for that. As of iOS 8 there are also size classes that abstract screen sizes into regular or compact vertically and horizontally and are recommended way to adapt your UI.