When will this happen? Will it work as drop in for the libraries in the current version or is it for a future version of the Engine?
It’s in the master branch (future 4.8) - new PhysX 3.3.3 along with its source code.
Indeed. I fetch it just before the commit. Thx Dishwasher 
No problem. 
They’ve got an github repo too.
Note that UE4 developers should use the PhysX source included on the UnrealEngine Github repository. The PhysX source available in the GameWorks repository differs slightly from that in the UE4 repository, because slight changes that were made to suit UE4 would not work for some other customers and are not part of the PhysX main line.
That’s great with the PhysX 3.3.3 included!
Great! What if i make some changes to PhysX, do i submit to Unreal github or somehow to Nvidia?