问题
I have a question: If I created an app with ARC, what's the last version IOS compatible for my app? If I upload my app in AppStore, everyone can use my app? or only people with a device with a specific ios version?
回答1:
ARC is supported on iOS 4.0 with one caveat: automatic nulling of weak references is only supported on iOS 5.0 and above.
回答2:
ARC compiled applications work on devices with iOS 4 or better.
回答3:
ARC "magic" is done by the compiler, so it is safe to use with iOS 4 of newer. In fact, iOS 4+ is a supported target for ARC applications. Here's a link with more information about ARC: http://clang.llvm.org/docs/AutomaticReferenceCounting.html
来源：https://stackoverflow.com/questions/8312056/ios-automatic-reference-counting