Apple saw an early sign of this reported slowdown in March, when its Q2 earnings showed that while iPhone 6S upgrades were outpacing the previous year, they still weren't up to snuff with sales from users who upgraded to the iPhone 6 is 2014. It's too early to say if the iPhone 7's slower sales are enough to make it the company's first device not to outsell the previous model, but we'll know soon enough: Apple's next quarterly earnings are set to drop sometime at the end of next month.