Does an app compiled with base sdk 5.0 will work on iOS4.x?

Does an app compiled with base sdk 5.0 will开发者_StackOverflow work on iOS4.x ?

I have made deployment target to 4.0. Will ARC work on iOS4.x devices. Is there a way to support both in a same app? If I am using ARC in iOS5, will memory management occur properly in iOS4.x devices?

Apple has stated that ARC will work in iOS 4 (not sure if they mentioned a specific version or if it includes iOS 4.0). But, I don't think you can submit ARC applications until iOS5 is out...

ARC is a compiler level feature. So it will not be affected by SDK. Apple will support ARC on 4.0 and 5.0 However, as on date, you cannot submit an app built using a beta version of Xcode.

If deployment target is set to 4.0, the app will support all higher versions iOS including 4.0. So the answer is YES.