Im using xcode4.6 for retina display screen size. When i use Deployment target 5 i didn't get any warnings. When i use Deployment target 6.1 i get warnings shouldAutoRotation is deprecated. But i used both shouldAutorotateToInterfaceOrientation, willAnimateRotationToInterfaceOrientation in same viewcontroller.m file for iphone4 &5. I have plan to upload my app. Which Deployment target i use for app works in both iphone4 &5. If i use Deployment target 6.1, my app will work in iphone4? or it will work on only iphone5?. (or) app store reject my app or not for getting warnings?
It's "deployment target", not "development target". The deployment target defines the minimum version of iOS your app supports. If you set it to iOS 6.1 then your app will only work on devices that have iOS 6.1 or later installed. If you set it to iOS 5.0 then your app will run on any device with iOS 5.0 or later.
If you set the deployment target to 5.0 or 5.1 then your app must properly deal with the change in APIs. View controller rotation changed a lot in iOS 6.0. Therefore all of your view controllers must implement the older and the new rotation related methods. If your deployment target is 6.0 or later then you don't need to add any of the older 5.x rotation related methods.