Default [Q] Who updates the firmware on my moto?

Hello,

I'm in Wisconsin and I got a moto x from Cellcom. I can't find any information as to who officially updates my firmware since Cellcom is such a small company. Below is my build and system info.

System version: 139.4.5.ghost_row.LRA.us
Build #: 13.9.0Q2.X-191-TA-5

Thanks for any help!

Tom