Specify a Custom Notification Sound

Play a custom sound when push notifications arrive by including an audio file in your app bundle. The SDK looks for a file named custom.caf in your app’s resources and plays it when a push message arrives. This feature lets you create a distinctive audio signal that helps users recognize notifications from your app.

Add a file named custom.caf to your project. The cloud push payload looks for a file named custom.caf.
Add the custom.caf audio file to the Copy Bundle Resources folder in Xcode for your app.
To prevent Xcode from using cached files, perform a clean build folder in Xcode. In the Product menu, hold the Option key and select Clean Build Folder.
Enable the custom sound option on the MobilePush Administration page. You might need to work with a Marketing Cloud Engagement admin to enable this option.