AT&T's version of the HTC One M8 is receiving a small update today, bringing the Extreme Power Saving mode feature to the phone. Though other models of the One M8 launched with the Extreme Power Saving mode, U.S. carrier versions were sent out the door before the feature could be enabled. Today it's AT&T's turn to push out the update (following up behind Sprint), and following confirmation earlier in the week that it would be heading out, members in our forums are starting to see the update already.