AUAudioUnit is only available on OS X 10.13 or newer

Hello all 🙂
I'm trying to rewrite my current audio app to use AVAudioEngine instead of AUGraph.
My deployment target is 10.11, however, whenever I'm trying to work with AUAudioUnit I get an error in XCode that says:

'auAudioUnit' is only available on OS X 10.13 or newer

But if you look at the reference for this API: https://developer.apple.com/documentation/audiotoolbox/auaudiounit

it clearly says that it's available on macOS 10.11+
Do I have to download and use an older SDK to support older platforms?


Thank you for your help. And for the amazing work Core Audio team has done lately!