An internal AT&T memo reveals that the company is beginning the switch to 4G compatible SIM cards for its upcoming LTE data network.
With the upcoming rollout of LTE data network, we will be transitioning our current SIMs to those that will also support LTE devices. During the transition, COR locations may carry or encounter up to eight different SIMs. It is important to use the correct SIM for the appropriate device. Verify the SKU which is printed on the SIM card as the various SIMs are similar in appearance.