The next generation of the iPhone will be revealed later on Wednesday as speculation mounts that it will do away with the headphone port and add a second camera on the rear of the device.
The 11th generation of the smartphone is set to be called iPhone 7, with the reported headphone port removal enabling Apple to make the device thinner and encouraging users to move to wireless earphones.
There have also been reports that wired headphones could be made available that connect through the phone's Lighting port, currently used for battery charging.
In July the tech giant announced it had sold the billionth unit of its smartphone, first introduced in 2007 and the product that has become the driving force behind Apple's rise to one of the most valuable companies in the world.
Chief executive Tim Cook will lead the unveiling at a live event in San Francisco, and has previously spoken of the success of the device.
"iPhone has become one of the most important, world-changing and successful products in history," he said at the time of the billionth sale.
"It's become more than a constant companion - iPhone is truly an essential part of our daily life and enables much of what we do throughout the day."
Reports have also suggested Apple could use the event to introduce a new version of the Apple Watch, the firm's wearable device that is yet to be given a hardware upgrade since it was launched in early 2015.