I was going to make an official announcement on the subject but its great you ask.

We are to make all of our current P3dv2 compatible sceneries P3dv3 compatible with their respective installers.

We are working on the update for KMIA which is a big one, and we expect to include a P3dv3 installer on release. Thereafter we will progressively work on the installers of the other scenery in order for it to be P3dv3 ready.

As far as I know, all of our P3dv2 compatible scenery work correctly in P3dv3, you have to point to the correct folder structure in order for it to work right.

we will let you folks know further on this in the coming days...