3.6 coming soon in pro, currently 3.5
It is controlled by Anaconda releases. If you want to be on bleeding edge, just produce a separate Anaconda distribution for testing, or it is just simpler to follow the discussion on the python lists or simply check on the changelog for python to see what is new
https://docs.python.org/3.7/whatsnew/3.7.html
Nothing major affecting gis world between 3.6 and 3.7 so you should be good for a year or two.
Numpy, Scipy and matplotlib (plus others) have had major changes in the last few years. and they are/will be as current as Anaconda permits.
If you want python. 3.x... use Pro, or just be careful working with it in ArcMap