This might be a stupid question, but does Objective-C have versions? Objective-C was always talked about in terms of the iOS version, even when the language itself was changing (eg blocks).
New Objective-C features are introduced with new versions of the compiler (and Xcode tools/SDK), but each feature may be deployed on different versions of iOS/OS X (depending on how much support they need from the underlying runtime/operating system). This table breaks it down: https://developer.apple.com/Library/mac/releasenotes/Objecti...
The language itself hasn't had any official version numbers since 2.0 (in 2006), but the runtime has (not very public) version numbers if you look at the source: http://www.opensource.apple.com/source/objc4/