What about "us" the new people (aka yours truly) who have only P6 and have been working hard to make a decent product to sell in the future? I don't know what i'm going to do cause i don't have P4, PP or P5 to test.
The few differences i'm aware between P4 and P6 besides the shader nodes in the material room, are the thumbnails files format and the bumpmaps.
Either i try to focus on a P6 specific figure like Miki or Koji (which are awesome, btw) or.. i throw away all my work with V3 so far?

Decisions decisions :(