Possible Duplicate:
Enabling auto layout in iOS 6 while remaining backwards compatible with iOS 5
My boss want me do to an App compatible with iPhone 5/4/4S and iOS 6/5
Is it possible ?
Will i be able to use NSLayoutConstaint ?
You can create a single app that supports anywhere from iOS 4.3 on up and it will work on all devices that supports iOS 4.3 or later (or 5.0 and later if you choose).
However, NSLayoutContraint is only in iOS 6.0 and later. You will need to use other mechanisms for the app to support iOS 5.x.