iPhone 15 lineup brought changes from iPhone 14.

Standard models have Dynamic Island, upgraded cameras.

iPhone 15 Pro introduces a new Action Button.

iPhone 16 Pro may feature a smaller Action Button.

Prototype shows redesigned button layout.

Apple testing unified Volume Buttons. Four prototypes explored different button designs.

Options include small Action Button with unified Volume Buttons.

iPhone 16 Pro testing a flushed Capture Button. Project Bongo initially aimed for haptic buttons.

Haptic buttons didn't make it to iPhone 15 Pro.

Apple explores capacitive Capture Button for iPhone 16 Pro.

"Proto2" design maintains iPhone 15 Pro's Action Button size.

Plenty of time for testing before iPhone 16 Pro launch.

Details on button layout to be revealed closer to production.