806.4 was added to the IRC in 2006. Unvented conditioned attic assemblies are permitted if they are constructed as specified in 806.4. The gist of it is that the insulation, air barrier, and vapor retarders must be placed on the underside of the roof deck instead of at the ceiling joists. In a space like the one in your pic, there probably will not be a way to access it once the ceilings are finished, so you won't be able to determine if it was done properly. An infrared camera could probably be used in this situation to at least determine whether the insulation is in the proper place.