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I've begun developing my first iOS app with Xcode 4.2, and was targeting iOS 5.0 with a "utility application" template (the one that comes with a FlipsideViewController). I read that since ARC is a compile-time feature, it should be compatible with iOS 4 as well, so I attempted to target my app to 4.3, and try compiling it. When I do so, I get this error: FlipsideViewController.m: error: Automatic Reference Counting Issue: The current deployment target does not support automated __weak references It is referencing this line: @synthesize delegate = _delegate; That variable is declared as: @property (weak, nonatomic) IBOutlet id <FlipsideViewControllerDelegate> delegate; I understand that "weak references" are not supported in iOS 4, but I don't really understand why I would want to use a weak reference to begin with, nor can I figure out how I would rewrite things to avoid using it, while still taking advantage of ARC (after all, it's su...

In apple documentation I saw that minimal requirements for ARC is iOS 4.3, but on WWDC 2011 video they talk that minimal requirements in iOS 4.0. On what minimal iOS version ARC will work? Will ARC work on iOS 4.0?

I have a view in my storyboard which I assigned an identifier called "MainView". However if I add its view to the subview, everything that follows produces a crash (e.g. pressing a button) MainViewController *mvc = [self.storyboard instantiateViewControllerWithIdentifier:@"MainView"]; [self.view addSubview:mvc.view]; This is the action triggered by the button : (MainViewController.h) -(IBAction)showUsername:(id)sender{ [testLabel setText:@"username"]; } and the crash log : -[MainViewController performSelector:withObject:withObject:]: message sent to deallocated instance 0x44e0810 I use ARC.