How can I tell if my cable connection is DOCSIS 3.1 or 3.0?

I just installed a new Motorola MT8733 modem and the connection light on the front comes on a steady green. According to the manual this indicates that the coax input is at DOCSIS 3.0 even though I have the Gigabit Extra plan from Xfinity. I there some place other than the LED that says what DOCSIS level I'm on?