Dear G,
I've a December 2019 Model XLR, and I got the update last week. After I went thru a charge cycle, the charge status started reporting the longer-range (approximately 350 miles vs. the original approximately 325 miles), but I've seen no difference in the real world range. Admittedly I've only been driving it for a week that way, but all it looks like is a bigger mismatch between the EPA range and what we get on the road.
The ongoing energy monitor is the only way I know of to get an accurate assessment of your range. (This information is also what's used if you're using trip navigator to tell you what your percentages of remaining power will be.)
Like so many others, I would love it if Tesla would change the software so that the little battery indicator on the dashboard showed the real range, not the EPA range.
pax / Ctein
[ Please excuse any word-salad. Dragon Dictate in training! ]