Following signs of new Side Button functionality in the iOS 26.2 beta 3 update, Apple developer documentation has confirmed that assigning a third-party voice assistant to the Side Button will be a feature available to iPhone users in Japan.

Developers are able to set up an App Intents framework that will allow voice-based conversational apps to be launched directly from the Side Button in Japan.

Right now, a long press on the Side Button activates Siri, and there is no option to change that. Japanese…