What type of reference does NSNotificationCenter keep for 'observer's & 'object's?

Question

Can anyone clarify/elucidate the situation with respect to -[NSNotificationCenter addObserver:selector:name:object:]?

• What types of references are

Answer 1

Current situation in 2016:

iOS 9 has changed NSNotificationCenter such that it weak references the target object.

That also to say you no longer have to removeObserver in when the object is dealloc.