Drotek Pixhawk 3 Pro

is anyone using the Drotek Pixhawk 3 Pro? For more than 6 month I was using the PX4 Pro firmware and it worked quite well. Now I have seen a firmware (beta) for the Drotek autopilot and installed it, hoping finally to get access to the battery 1 and 2 status using a Drotek PMU. Unfortunately in Mission Planner the Drotec PMU is not in the drop-down menu.
Using the new firmware as well the selection for ‘simple’ and ‘super simple’ mode, landing gear e.g. in the advanced tuning are greyed out.
I would appreciate any information or experience with the Drotek autopilot. Thanks in advance!