Thank you for reaching out!
Unfortunately, there is no option to control the device using MQTT, only to read its data.
Parameters, that can be read using MQTT can be found here.
As for controlling the output, I'd recommend using JSON-RPC. This method allows both - management and monitoring and can be automated quite easily. If automation is not needed, simpler options like SMS (set pin state using UCI command via SMS) or a Call can be used.
Let me know if any help is needed with the configuration!