With the latest manufacturer updates for Apple devices, namely iOS 12 (mobile) and OSX Mojave (computer), support for Apple AirPlay (version 1) was unfortunately discontinued by the manufacturer.
The AirPlay interface built into the iTeufel Air/Blue can thus no longer be used. For hardware-technical reasons, compatibility with the successor, AirPlay 2 can no longer be enabled via a firmware update.
Therefore, AirPlay function is no longer supported on the iTeufel Air & iTeufel Air Blue under current Apple operating systems (IOS 12 and OSX Mojave).
However, you can still control the iTeufel Air Blue via the Bluetooth interface or use the line-in.