Hi,
Modbus MQTT gateway and Modbus TCP over Serial gateway (TCP to RTU), can both be found under Services -> Modbus in the WebUI.
More information about these functionalities can be found here and here.
Also, if you are having problems finding some functionalities on the newer firmware versions, it can be that functionalities were removed to save flash memory, but they can easily be downloaded from Services -> Package manager if needed.
Kind Regards,
Andzej
