The cellular band (Band Class 5) is not a future Sprint band. Sprint uses band class 26 which happens to encompass the cellular band, but Sprint has no cellular spectrum; they're using band class 26 for their SMR spectrum, which the at&t iPhone does NOT support. As far as PCS, they are currently using the PCS G block which requires band class 25, not band class 2 which is what the at&t iPhone apparently has.