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

The only really required thing to do is to add a launch image named "Default-568h@2x.png" to the app resources, and in general case (if you're lucky enough) the app will work correctly.

In case the app does not handle touch events, then make sure that the key window has the proper size. The workaround is to set the proper frame:

[window setFrame:[[UIScreen mainScreen] bounds]]

There are other issues not related to screen size when migrating to iOS 6. Read iOS 6.0 Release Notes for details.