dLive Director v1.84 won't talk to C3500 v1.85

So… I take it the version of dLive Director is required to match the firmware on the Surface? When will Director v1.85 be released?

I believe it does. It looks to me like 1.85 is there: https://www.allen-heath.com/dlive-home/software/

So… I take it the version of dLive Director is required to match the firmware on the Surface? When will Director v1.85 be released?

what you mean with released?
it is already released I use it since some months already

Up to now, the Director version was adapted to each new firmware version.
You can find the Director 1.85 for MAC and PC under the link shown by Brent H.