Carrier Tmobile band 71 on XS Max

[iPhonemaster5S]

After getting my XS Max yesterday I was having difficulty getting the sim card that was in the phone to activate and transfer my phone number. Starting to get impatient I then took the sim card out of my 7 Plus and put it in the XS and everything worked like a charm. My only question is that will I still be able to take advantage of band 71 and everything else or is the sim card too old that it won't support it?

 

[frumpy16]

After getting my XS Max yesterday I was having difficulty getting the sim card that was in the phone to activate and transfer my phone number. Starting to get impatient I then took the sim card out of my 7 Plus and put it in the XS and everything worked like a charm. My only question is that will I still be able to take advantage of band 71 and everything else or is the sim card too old that it won't support it?

The SIM card does not determine the bands the phone can use. Don't buy the carrier BS that you need to use a new SIM with a new phone "to ensure the latest features and support." They're trying to secure their bogus upgrade fees.

 

[seezar]

You’ll be fine using your original SIM card. That’s what I did and by doing that potentially saving getting an upgrade fee charged. The phone itself is responsible for using different bands not the SIM card.

 

[Juanefny]

I called to activate and T-Mobile told me just to put the old SIM card on the new phone...