" KC-46 Pegasus aircraft are now expected to arrive at their first basing locations by late summer or early fall 2017.
The KC-46 was most recently scheduled for a spring 2017 arrival at Altus Air Force Base, Oklahoma, the first formal training unit location; and McConnell AFB, Kansas, the first active duty-led Pegasus main operating base. But after a schedule risk assessment, Air Force officials determined the fielding timeline needed to be extended."
Further here :
Boeing and U.S. Air Force Adjust KC-46 Tanker Schedule | at DefenceTalk