There might not be enough iPhone 7 units at launch (AAPL)

The iPhone 7 is coming out next month. But it might be difficult to buy one immediately after it comes out. 
Apple is facing a supply shortage of its still unreleased device, Nikkei reported on Friday. The problem is certain components are proving trickier to make than expected. 
In particular, Apple's suppliers are having trouble making enough of the double-camera module expected to be used on the larger 5.5-inch iPhone and a new waterproof speaker part used on both models.