We now have P3D V5 and will talk about some of the technical problems here.
Materials and objects not appearing: From what we can see, the reason why our P3D V4 compiled models don't work, is probably by mistake not by design. With the P3D V4 SDK, you could use new PBR Material or classic materials (or a mixture in the same model). We only used PBR for the ground.
With P3D V5, only the P3D V4 compiled ground using PBR works in P3D V5, the P3D V4 compiled classic material doesn't work. The dumb thing is that the old P3D and FSX models do work, this is why we think it's a LM mistake and bug.
We tried to compile Luton with FULL PBR material settings for V5 and yes so far it does seem to work, so thats good news.
Night Lighting: Is it just us, or is P3D V5 now a lot darker? Also dynamic lighting does not work.
Could this be another bug, or perhaps a change in the effects file format, we will look at the SDKA.