In the mission planner, it is 4.4V.
In the description there in MissionPlanner it is more generic and suits ordinary Lipo cells in this case.
If you connect the flight controller to MissionPlanner and press Alt A the dialogs step you through setting those values correctly and offers values for different battery types.
So have you done all the initial calibrations that are required and set up battery voltage and current monitoring?
We performed various calibrations.
I pressed Alt A and entered the required information. The following screen was displayed.
So, your question has been answered.