Tech gaint Apple will launch iPhone 15 series in late 2023 and there are the next iPhones will accept USB-C, which has already been announced, and Apple is reportedly intending to get rid with the physical button design. 

According to business analyst Ming Chi Kuo tweet, the iPhone 15 Pro and 15 Pro Max versions may use solid-state button layouts. This will enable touch-based interaction without the need to physically press the button, similar to the design of the home button on the iPhone 7, iPhone 8, and some other models.

Taking to Kuo’s tweet, "My latest survey indicates that the volume button and power button of two high-end iPhone 15/2H23 new iPhone models may adopt a solid-state button design to replace the physical/mechanical button design"

https://twitter.com/mingchikuo/status/1585852274680950784

It has been speculated that the iphones will contain taptic engines that are "placed inside on the left and right sides to provide force feedback to make users feel like they are tapping real buttons." This means that Apple will have extra room within the smartphones to support a bigger battery. The next iPhones will contain three Taptic Engines rather than the one vibration motor present in the current models. 

The iPhone 15 series is reported to eventually include an USB-C port in addition to solid-state button layout. The Pro variants are most likely to keep the same hole-punch display style as the iPhones from this year. They will be iOS 17-compatible and operate on Apple's newest A17 Bionic chipset.