Apple's new Apple SIM card in the iPad Air 2 and the Retina iPad mini 3 is designed to be universal, usable across a variety of wireless carriers in the US and UK, including AT&T, Sprint, T-Mobile, and UK's EE.
According to user reports in the MacRumors forums and on Twitter, however, AT&T is not supporting this interchangeability and is locking the SIM included with cellular models of the...