Okay, so this is just a straight run with the professional mod. all the sounds,textures,models,etc are taked of scp:cb versions v0.1,v0.6.6 and v1.2.4 and ported to scp:cb v1.3.9.
this mod change textures,models and sounds of older versions of scp containment breach to the newest version of scp:cb (v1.3.9). Scp:cb classic edition is a middle reconvertion of textures,models and more of the normal scp containment breach.