Pump will return HEAD = 0 when RATE == 0, in results. Previously HEAD had a value, but was meaningless, because there is no stream/fluid through the pump.
It is no longer allowed to use SIMPLIFIED_COMPRESSOR_TRAIN with unknown stages or unknown charts (GENERIC_FROM_INPUT or using MAXIMUM_PRESSURE_RATIO_FOR_STAGE) in a COMPRESSOR_SYSTEM. They can not be fully predefined, and can then potentially change between operational settings.
As a consequnence of the item above, it is also no longer allowed to use COMPRESSOR_WITH_TURBINE with unknown stages or unknown charts (GENERIC_FROM_INPUT or using MAXIMUM_PRESSURE_RATIO_FOR_STAGE, ie. using SIMPLIFIED_COMPRESSOR_TRAIN) in a COMPRESSOR_SYSTEM.