PhysX in 3DS MAX switch to 2.8.4?

I found this strange that each time I open 3DS Max, the mini script listener shows PhysX SDK switch to 2.8.4.
However I am using PhysX: 3D Studio Max DCC plug-in for PhysX 3-3-4. It should be 3.3.4 not 2.8.4. I wonder why it shows this notification.