In a Branch thread stemming from discussion of an iPhone production report, Daring Fireball’s John Gruber wrote that he’s heard that iOS 7 is “running behind,” and engineers have been moved off OS X 10.9 to work on the newest iOS. According to The Wall Street Journal, Apple is expected to ship iOS 7 “around midyear.” An overhaul of the user interface is expected, courtesy of Jonathan Ive’s involvement. Gruber…