At least on ATT in the US the iPhone 5 is not on the "supported" list, the 6 and up is. https://www.att.com/idpassets/images/support/pdf/Devices-Working-on-ATT

At least on ATT in the US the iPhone 5 is not on the "supported" list, the 6 and up is. https://www.att.com/idpassets/images/support/pdf/Devices-Working-on-ATT-Network.pdf https://www.att.com/idpassets/images/support/pdf/Devices-Wor...