The Apple executive who oversaw development of the troubled iPhone 4 is leaving the company.
Mark Papermaster has been head of Apple's iPhone and iPod hardware engineering department since 2009 when he joined the company from IBM.
His departure is widely believed to be linked to the problems with the antenna on the iPhone 4.
Apple would not comment on the reasons for his departure or whether he resigned or was fired.
Soon after the iPhone 4 was released in late June many owners began reporting that it dropped calls. Evidence emerged that signal strength faded when the phone was held in a particular way.
The problem was traced to the iPhone's use of its metal casing to house its antennas. Bridging the short gap between two antennas on the lower left-hand side of the case caused signal strength to leak away.
An investigation by the influential Consumer Reports organisation confirmed the problem and led to it declaring that it could not recommend the product.
Initially, Apple downplayed the problems but the continuing furore led it to offer free cases to all iPhone 4 owners as these stop the gap being bridged. Mr Papermaster was not present at the press conference where the offer to iPhone 4 owners was unveiled.
An Apple spokesman said Mr Papermaster's responsibilities would be assumed by Bob Mansfield who currently oversees engineering efforts for the company's Macintosh products.
He also has a role in guiding development of some of the components for the iPhone and iPod Touch.
Mr Papermaster worked at IBM for 25 years before joining Apple. Although hired in 2008 he did not start work at Apple until mid 2009 because IBM filed a lawsuit saying his taking up the post breached terms of his contract.