I’ve been testing out PaperKit from beta 1 up until 3, then took a break and on my return at beta 7 I find that the .drawing property of the PaperMarkup data model has been removed, i.e. a PKDrawing can no longer be added / modified on PaperKit. Also, the shape recognition feature seems to have been removed.
I see this as a tremendous drawback. I filed feedback already: FB19893338 Please bring it back.