A few years ago, Apple was rumored to be developing solid-state buttons for its iPhone 15 Pro series. While that did not pan out, a new report from a Chinese tipster Instant Digital suggests Cupertino is currently testing solid-state buttons for its upcoming 20th anniversary iPhone model.
Apple is expected to launch a special anniversary edition iPhone next year, which will feature a quad-curved screen that blends with the sides of the device. The new report suggests that Apple has already done testing of the solid-state buttons, complementing the all-glass look of the device.

iPhone 20 mockup (credit: MacRumors)
According to the new report, the solid-state buttons passed rigorous testing scenarios with use cases like users wearing gloves, pressing the buttons with wet hands and in extreme temperature conditions. The post also mentions that the new buttons are powered by a dedicated low-power chip which registers presses and provides haptic feedback even when the phone is completely switched off.
In addition to the solid-state buttons, the 20th anniversary iPhone will allegedly bring under-display Face ID and selfie camera capabilities inside a dual-layer OLED display, aka tandem OLED. The display (and the sides) of the device are said to feature next-gen Ceramic Shield protection, which will offer improved scratch resistance.

Apple iPad Pro series (2024) debuted tandem OLED displays
Another interesting fact is that the device will not have a physical earpiece like all previous iPhones, but it will also feature “under-display sound”. We can only assume this will work like the Pixel 5 and LG G8 under-display ear speakers, but it remains to be seen.
Outside of the display and solid-state buttons, the next-gen iPhone is expected to bring a 6,000mAh battery with reverse wireless charging capabilities.
Source (in Chinese)
