Possible duplicate:
Support for older versions of iOS
I plan to abandon iOS3.X support in my next app update (change the iOS deployment target level from 3.0 to 4.0)
I was still focusing on iOS 3.0, but I can’t test my Xcode project with the old SDK anymore (I can’t run the iOS3.0 simulator).
Do you know if this is possible? What will happen to iOS 3.X users, will they see the update? (I do not want user complaints)
source
share