Change midi channel with expression maps?

What is the timescale for this addition? e.g. will it be a few months or more than a year. I ask because I haven’t actually purchased Dorico yet, I’m just experimenting with the free trial. The main reason I started looking at Dorico is that my current notation software doesn’t really have this capability either. Bidule looks like it would be about $100 in addition to the crossgrade price for Dorico, so this is a consideration for me. BTW, I have also tried some apps to interface the notation program’s output midi with my DAW…sometimes it sort of works, but tends to crash a lot.