X-CTU 5.2 finds my Xbee/Sparkfun USB, X-CTU 6.4 does not, why?

I’m using Windows 10 and USB.

I have a sparkfun (as well as a parallax) USB interface board for Xbees.

I can see and program them with X-CTU 5.2 but if I use X-CTU 6.4 it does not find it.