Information On The Built-In Rechargeable Battery; Installing Firmware Updates - Sennheiser CX 400BT Series Instruction Manual

Care and maintenance of the earbuds/charging case
30 | CX 400BT True Wireless
Information on the built-in rechargeable
battery
Sennheiser ensures and guarantees that the rechargeable batteries
perform at their optimum upon purchase of the product. If, upon pur-
chase or within the warranty period, you suspect that a rechargeable
battery is obviously defective or if a charging error/battery error is
displayed (> 7), stop using the product, disconnect it from the power
supply system and immediately return the product to any Sennheiser
service partner.

Installing firmware updates

Firmware updates can be downloaded free of charge from the Inter-
net using the Sennheiser Smart Control app.
▷
Connect your earphones to your smartphone and start the Smart
Control app (> 19).
▷
The app provides information on available firmware updates and
guides you through the installation process.