Because Bodypaint2 can be used as a module in C4D8, and, as a standalone, also uses much of 8's functionality,

and because there is no mixing of 7 or earlier and 8 files possible,

I suppose that BP2 can only be used with C4D8.

Max, Maya, LW ok, but no C4D6 or 7?

This would be a real gumption trap