AT&T expected to push Android 7.0 Nougat to Galaxy S7 edge units in "early Spring"
On top of that, the South Korean company only made it available in those countries where the beta program was enabled, which means Galaxy S7/S7 edge owners in China and the UK are the only ones that can download Android 7.0 Nougat on their smartphones.
The information has been recently confirmed by an AT&T rep, who said that the carrier is already testing the beta and estimates that a final build could be rolled out in March or even April.
Obviously, AT&T's plans can change anytime and Galaxy S7/S7 edge owners could receive the update much earlier, but based on past experiences, the carrier doesn't usually releases major Android updates until after the market launch of the next Galaxy S flagship, or around that time.
Things that are NOT allowed: