For the past decade, Apple has seemed invincible. Its new announcements are so heavily shrouded in secrecy and its products are so widely used (can you imagine a world without i-Things?) — that it has seemed impossible for the tech giant to falter.But today, Apple released some startling news: for the first time ever, iPhone sales declined from one year to the next. In today's quarterly earnings call, Apple CEO Tim Cook said that iPhone sales slowed 16% from this same time last year, with the company selling 51.2 million iPhones in this year's post-holiday quarter, compared to 61 million in 2015.Is this the beginning of an Apple decline? In short, no. While the decline in iPhone sales sounds scary, Cook was quick to point out that the decline fit with company and industry expectations and said, "We would ask folks to look underneath the numbers at the details in them before concluding anything."In the call, Cook pointed to a stagnant market overall — smartphone sales across the industry haven't been so great recently, and for once, Apple wasn't the shining exception. But he remained optimistic, citing three places where most iPhone sales come from: upgrades, switches from Android, and people who are buying smartphones for the first time. Cook said that Apple has recently seen a larger number of people switching from Android phones than it has in the past. If the rumors are true and Apple does release the iPhone 7 later this year, it's likely that those iPhone sales will experience some major growth once again from folks wanting to upgrade their handsets.And while iPhone sales declined from this time last year, Apple saw a big growth in other areas including App Store revenue, the expansion of Apple Pay, and, of course, the Apple Watch , which just celebrated its one-year anniversary. Cook said that the sales of Apple Watches exceeded those of iPhones in their first year on the market and that he expected the recently lowered price (and stylish new bands ) to continue to boost Watch sales.So no, it doesn't look like Apple is going anywhere. If anything, today's news just builds anticipation for what the company has in store next.