If you have already set up Teufel streaming devices via an Android smartphone before, the following information is relevant:
The setup procedure changes slightly from app version 4.15 due to technical changes in Android (from the latest OS version): Instead of the familiar automatic switch to the wifi "Raumfeld Setup" in previous app versions, it is now necessary to perform this step manually.
Therefore, when prompted by the setup wizard, switch manually to the WIFI settings of your smartphone without exiting the setup wizard and select the WIFI "Raumfeld Setup" here. Then return to the setup wizard and follow the further steps (unchanged).