So, you have to use copy
If you have this property:
@property (strong) NSString *name;
You won't have any problem with NSString
-s.
But you could receive an NSMutableString
instance as new value!
So, you have to use copy
Objective-C @property declaration cheat sheet – http://git.io/objcproperty https://stackoverflow.com/a/11249723 Implementing NSCopying (or NSCopyObject() Considered Harmful) TMI #1: Objective-C Property Attributes