They will work, I have both and I can plug the older cams into the newer NVR. I haven't tried going the other way. My problem now is that the newer NVR is 8ch and came with 4 cams. However since everything goes through my network the 4 cameras from the older unit also show on the newer unit even though they're not plugged in physically.
I'm not sure what would happen if I got 4 more newer style cameras for the new NVR.