Quick question:
I have a set of Ultimate in a box and RS 2017 installed on my new bike.

For internal routing reason, and to make things easier, I was thinking of leaving the RS2017 caliper at the rear (since this is now the same S4 caliper as the ultimate) and replace only the RS lever with the Ultimate Lever. (instead of removing the whole rear RS guide to replace it with the whole Ultimate Guide)

Is it something compatible? I would see no reason why not, but since the ultimate as the contact adjustment that the RS lever doesn’t have, I was wondering if the caliper needed to be compatible too for that.
Thanks for your feedback !