I just got a Nexentro Zigbee Switching Actuator Mini (Schaltaktor Mini).
While it shows up as a “Generic UP Device” in the Lights section and the state seems to be read correctly from the device, the device does not stay on: Whenever I turn it on in the Phoscon-GW it switches on and directly off again (resp. off and on again), independently of the builtin mode of operation for the switch (switch vs push button) or the state of the attached switch.