What recent engine changes?

Even so, medierra has said they are not sure how much it will improve on specific users’ machines.

Part of the engine changes were for the XBox One port.

I’m not sure on this as medierra’s post above indicates no other changes will be made; so maybe for the Illusions system and/or the skill modifiers for the new high level legendaries.

See the Grim Dawn Expansion Development News for more info on the expansion (if you haven’t already), specifically the last FAQ on the new features for the expansion.