Don’t hold your breath guys they clearly made this so much more complicated than they had to. Take a look at this 9 year old thread. The argument that few people have more than 16 zones didn’t make any sense then and it makes little sense now. They simply for one reason or another don’t want to do this.
As previously I and others made clear that as user I just want to merge two seperate (Front Yard) and (Back Yard) control sets together (without running wires) that are currently being handled by two dumb controllers that work and have been working since I posted about this 5 years ago. It has nothing to do with having more than 16 zones.
I have 3 zones in the back and 3 in the front so 2 Rachio controllers would be purchased to acomplish this IF ONLY they saw this as a money making opportunity for the company. The fact that these threads have THE MOST VIEWS, had the most views then and now should move the needle at the company but for some odd reason they’ve dug their heels in that this is an “unwanted” feature. 
So I wait…check ever so often for when and if they finally add it…because my dumb controllers continue to function just fine. I have no reason to buy a smart controller unless this convenience feature is added since manually scheduling a smart controller is no different than having two dumb units.
9 YEAR OLD Suggestion Still on the table…
I love the simple intuitive UI that is miles ahead of competition but this is such a thorn that for me takes away the entire value proposition of ditching my dumb timers…that do work.