While the volume and power buttons should have had a total overhaul on the upcoming iPhone 15 Pro and Pro Max, technical difficulties caused Apple to change its mind at the last minute to keep the classic buttons that we know.
Customizable Ringer/Silent Switch?
There should, however, be a notable change for the ancestral Ring/Silent switch, present since the very first iPhone in 2007. Indeed, it should be replaced by a simpler button, internally called the "ring button". or "action button", similar to the Action button of the Apple Watch Ultra, and which can be personalized by the user. Source: macrumors