Question

Before iOS5 most people did it in dealloc. By iOS5 that functionality migrated to viewDidUnload. Now that viewDidUnload is deprecated and never gets called, it would seem we will have to find new spot to unregister our observer.

Question is, where?

Answer 1

From the Apple docs views are never unloaded anymore.

Prior to iOS 6, when a low-memory warning occured, the
UIViewController class purged its views if it knew it could reload or
recreate them again later. If this happens, it also calls the
viewWillUnload and viewDidUnload methods to give your code a chance to
relinquish ownership of any objects that are associated with your view
hierarchy, including objects loaded from the nib file, objects created
in your viewDidLoad method, and objects created lazily at runtime and
added to the view hierarchy. On iOS 6, views are never purged and
these methods are never called. If your view controller needs to
perform specific tasks when memory is low, it should override the
didReceiveMemoryWarning method.

So, you put your unregister command into -(void)dealloc or -(void)didReceiveMemoryWarning. Even in Arc -(void)dealloc get’s called, you just can’t have a call to [super dealloc].