Aeroplane Heaven has posted an update on their progress with the Spitfire for MSFS 2020. Along with some new screen shots they report that they have begun testing the Merlin engine and are nearly complete on the flight modeling.
We've begun testing the Merlin. Working on gravity feed for the carb and boost cut-out. We're nearly there on the flight modeling so she's not far away now. There's full function in the cockpit including the primer control, oxygen, landing lamps controls for selection and dip and an awful lot more.