Tyler Rogoway in The War Zone has a recent article posted on the repeatedly delayed Boeing KC-46 Pegasus tanker. The apparent plan, if true, to retire all KC-10s before the "youngest" KC-135s was surprising to me. In addition, the KC-Y program (KC-10 replacement) could be skipped, and go straight to the KC-Z (someday). Additional info on various tankers in linked stories within this article.
http://www.thedrive.com/the-war-zone/19332/the-kc-46-pegasus-tanker-program-is-still-a-mess
http://www.thedrive.com/the-war-zone/19332/the-kc-46-pegasus-tanker-program-is-still-a-mess