To bad, my old heater had opentherm, with the OTGW I could intercept the packets between the heater and thermostat, change values (eg: date/time), issue command

To bad, my old heater had opentherm, with the OTGW I could intercept the packets between the heater and thermostat, change values (eg: date/time), issue commands (set room temperature) and add missing functionality (outside temperature for heating curve), it was ideal in every way. But I moved and my current heater has a proprietary protocol over rs485 so its a no-go for the OTGW.