Greg Christie may have played a key role in developing the first iPhone, but he won't be hanging around Apple for much longer. The company has partly confirmed a 9to5 Mac report that the high-profile interface designer is leaving the company later this year after nearly two decades of working at 1 Infinite Loop. Just why he's hanging up his badge isn't certain. The 9to5 story contends that Christie and senior design VP Jony Ive had a "falling out" over iOS 7's design direction, prompting Christie to head for the exit. An Apple spokesperson, however, says that the executive has been "planning to retire" and notes that he "worked closely with Jony for many years." If there are any sour grapes involved, it's not apparent from Cupertino's official position.