To use custom ringtones and notification sounds on Android, please perform the following steps:
Copy your ringtone sound files to the folder “ringtones” and notification sound files to the folder “notifications”. Alternatively, you can use third-party apps like Ringtone Maker, which will take care of copying the files to the correct location for you.
In the Threema app, navigate to “Settings > Sounds & Notifications,” and select the ringtone or notification sound you want to change. This will take you to the notification settings, where you can change the ringtone.
