Hi all, I recently moved to the US-Mexico border and would like to switch to T-Mobile to take advantage of their free international data and texting when on the Mexico side. I currently have an ATT iPhone 6 that is under contract and is locked to the ATT network. I visited the T-Mobile store today and they informed me that even if I cancel my contract with ATT and have them unlock the phone, that it will still not be able to take advantage of the full speed of the T-Mobile LTE network. This sounded strange to me as I was under the impression that the ATT and T-Mobile phones were identical and would work on all the same frequencies. Can anyone confirm that the information I was given is correct? Thanks all!