As per this post :
V3 and V4 are identical. I suspect that if there is a difference when printing the same file with the two resins, that it may have more to do with the fact that Formlabs updates the print settings only for the most recent version. This would mean that tricking the printer into thinking it’s setup with V3 instead of V4 may do the trick… that would require either reprogramming the cartridge chip, pouring V4 into a V3 cartridge or using Open mode.