Firmware updates are available free of charge. You can download them from the Internet using the Sennheiser Smart Control app.
Make sure that the rechargeable batteries are fully charged before updating (> Charging the rechargeable batteries using the USB cable).
Take the earbuds out of the charging case before updating and do not reinsert them into the charging case during the update.
Connect your earbuds to your smartphone and start the Smart Control app (> Installing the Smart Control app).
The app provides information on available firmware updates and guides you through the installation process.
Avoid connecting or disconnecting the USB power supply during the update process.