Industry watchers expect the iPhone 8 to go on sale much later than normal.
Traditionally, new Apple iPhone models would go on sale at the end of September, just two weeks after the big launch events watched by millions.
While the update to the iPhone 7 and iPhone 7 Plus handsets should be available before October, some believe the iPhone 8 may not arrive until November.
Apple is reported to be having trouble implementing wireless charging on the new iPhone, a popular feature on Android handsets such as the Samsung Galaxy S8.