That looks like the 3.0.1 version where the motor mounts to the 40mm ball bearing housing. If you look at the latest 3.1 files they have created a new motor mount that connects to the piece of aluminum in the middle.
See the blue piece in the middle, that’s the new motor mount
The difference between the 3.01 build and 3.1 build, is they changed the endstops from photo sensors to mechanical endstops. There’s a few different parts that’s different. Both the sprockets that go into the 40mm bearings are different (one has the mechanical endstop nipple that triggers the endstop) then there’s a spacer that goes in between the 40mm bearing and the sprocket / gear.
List of parts that’s different:
axis_gear.fcstd (Changed Part)
axis_gear_as5601.fcstd (Changed Part)
axis_gear_flange.fcstd (Changed Part)
axis_spacer.fcstd (New Part)
homing_ring.fcstd (New Part)
motor_mount_plastic.fcstd (New Part)
switch_endstop_holder.fcstd (New Part)