The type or namespace name 'ARExtensions' does not exist in the namespace 'UnityEngine.XR

Unity Engine
1

So opening an older AR project in 2019.2 (release) and getting compile errors

The type or namespace name ‘ARExtensions’ does not exist in the namespace 'UnityEngine.XR

The type or namespace name ‘ARSystemStateChangedEventArgs’ could not be found

I’m using ARFoundation + AR Subsystems + ARCore + ARKit XR plugin 3.0.0 preview.4

Any feedback really welcome!

2

Some clues here: