With iOS 26.2, users in Japan will be able to use third-party voice activated apps besides Siri

A new document in Apple’s Developer blog confirms that users in Japan will, with iOS 26.2, be able to reassign the side button to launch third-party voice-based conversational apps, rather than Siri, notes 9to5Mac. 

Apple has shared a new document on its Developer blog with new details, including the fact that this feature will be limited to Japan, at least for the time being. From the document: By adopting the App Intents framework and offering App Shortcuts, you let people instantly access app functionality and integrate it with system experiences like Spotlight or App Shortcuts. For example, a person might place an App Shortcut you provide on the Action button. In Japan, people might place an action on the side button of iPhone that instantly launches your voice-based conversational app. People expect the voice-based conversational functionality to be instantly available when they launch your app with the side button, so make sure to let them immediately use it by starting an audio session – for example, with AVFoundation.