From end of September 2020 all the switches with the circular electronic unit will have a built in heater. It covers the products:
HBSC2, HBSR, HBSO and HBOR. The heater will keep the electronic circuit dry and warm in cold conditions. The heating will start at ambient temperatures below 5 deg C (41 deg F) and gradually increase consumption as the temperature decrease. The heater will increase the current consumption for the switch in low temperatures from 10 mA to 200mA.