It’s in the release notes here:
Added an option in the PERSONALIZE menu that is called TRACK SELECT that lets you decide how to select tracks and how that action relates to triggering the sound of the track.
Taken from feature req here: Digitone II Feature Requests - #58 by avantronica 
I will use this a lot because it makes the behavior much like the original & keys - and I play on keys so I appreciate being able to switch tracks with one finger press 