As I see, the ARKit plugin still use old
ARSessionConfiguration and so on) classes which was deprecated and now is not available in iOS ARKit (latest iOS 11 Beta). It should be renamed to just
ARConfiguration, as well as some other classes.
So, it’s not possible to build an iOS app with UE4’s ARKit…
I believe someone is already working on the plugin’s update, but can’t find anything related…
Maybe there are some issue in the tracker, or something?
UPD: in the UE4 github branch 4.18 there are several fixes for ARKit, so it seems ARKit will be available in 4.18.