Right now I have two SR3100 Rx that I think are fake, but they work fine. My DX4C is V1.0. I will not upgrade it because it may make it incompatible. I bought them as genuine, and they seem to bind and hold bind, but have not used them in a car yet. Still trying to figure out if they are genuine or not. I thought all the fake ones did not work with DX4C.