Ok will answer my own question then: function changeRGBGatewayColor(rgbColor, brightness) gatewayName = '<NAME OF YOUR XIAOMI RGB GATEWAY>' gatewayIDX = otherdevices_idx[gatewayName] url = 'http://<YOUR DOMOTICZ IP ADDRESS>:<YOUR DOMOTICZ PORT NUMBBER>/json.htm?type=command&param ...

I've a Domoticz version 4.9700 running and a Xiaomi RGB Gateway on firmware 1.4.1_157.0143. What I did found out is that you can control the brightness of build-in RGB light with: commandArray['Xiaomi RGB Gateway']='Set Level:'..tostring(10) - You can turn on/off the light with: commandArray['Xiaomi ...