My DX3 finally broke after 6yrs of use, the scoll roller broke while trying to select models.

I'm looking at getting the DX4s or 4r and was wondering if it will work with my other receivers. I just bought (2) SR310 receivers back in September and I'm finding mixed information about it being backwards compatible. I've read a few places that say yes it will work and then a few places that say, no it will not work and would have to buy all new receivers....

Any info or input would be greatly appreciated. I have a big race coming up in 2wks and need something soon.