Thanks! That was indeed a message I sent using the Console (serial connection).
Now I need to get hold of a temperature sensor, as the mDot developer board seems to have none at all...
There are sample programs at https://developer.mbed.org/platforms/MTS-mDot-F411/
I suppose these won't work anymore since we switched the gateway to TTN mode with a different AT command set?
Where do you plug in the DS18B20 Digitale temp sensor in the board?
And how does the TTN config relate to mosquitto exactly?