I downloaded the most recent Networx, to install on my new ASUS A88X build. Networx seemed to monitor my Huawei E8732 when attached to USB port.
But then I tried a ZTE MF91 hotspot via USB gateway, and couldn't find it in the monitored interfaces list. Next one I tried was the Sierra 320U 4G modem, but it wouldn't do that either. Normally Sierra modems turn up like litter in the interface list. With recent older versions I have had no problems just leaving it set to All Connections.
I have gone back to 5.2.7, because that's the only one I can find on my hard drives.