Looking for PhysX SDK used in Unity3D

We are starting a game project using Unity3d and we want to emulate the game logic server-side. Regretfully I haven’t found exact information regarding the version of PhysX used in Unity, but after reading the changelog I believe that it is 2.8.3. If it is possible could you provide a download link to the version of PhysX (for different platforms) used in Unity? Is it possible to emulate Unity behaviour of obects on pure PhysX?