LTE CAT M1 is a low power communication channel for LTE networks designed for IoT use. How do I check whether a network supports it or not?
Carriers' help desk does not know anything about CAT M1. That is understandable because most users don't need to know about it. I may try other ways of getting this information from them but I guess if the network is up and running, one should simply be able look it up using appropriate hardware. As of now, I have a LTE phone (Nexus 5x) and the carrier's SIM.