On Wednesday morning, Sydney time, Apple CEO Tim Cook will take the stage for the first time in the Steve Jobs Theater at the company's new campus. The location represents a new chapter for the world's most valuable technology firm, and the event will usher in a new era for the iPhone. For the first time, Apple plans to unveil three new phones, including a premium model that will cast a halo over the rest of the line, and perhaps over the rest of the smartphone industry.

The new devices will not only be exciting for customers, but for investors as well.

The iPhone represents about two-thirds of Apple's sales, making it critical to the bottom line. A new iPhone launch means a strong holiday quarter that could also include more sales of other Apple products. The entire business relies on the gadget: it serves as remote control for the Apple TV box and upcoming HomePod speaker, it's currently tied to the Apple Watch, syncs with the iPad and Mac, and is home to services like Siri, Maps, and Apple Music.

Beyond the iPhone, the company is also planning a version of the Apple Watch that connects to wireless networks and an upgraded Apple TV. As previewed in June, Apple is also preparing important software updates for all of its platforms — iOS, watchOS, macOS, and tvOS — and is likely to showcase some features from those this week.