But if I don't put in an AT&T SIM card then it will never update? (Because its likely that I will never have an AT&T sim card in this.)


I think the band info you posted is far beyond my knowledge or capability. I don't really understand it and probably won't without a step-by-step guide. Hopefully ...

Thanks! I'm in the US at the moment--I just travel a lot. It just says no upgrades available, but that might be because it has a T-Mobile SIM? (So yes it is unlocked.)

Settings->Software usually says "up to date." Sometimes it says there was a problem updating the device. (From what I've read ...

I just got MR6500 as a refurb to use as a travel router when I'm travelling internationally and need to use a physical SIM.

Here is my device info:
Firmware Version: NTGX65_10.04.22.01
Firmware Build Date: 2023/01/11
Hardware Version 1.0
PRI Version 01.21
WebApp Version: MR6500-1A1NAS_05.00.63.00 ...