Mercenary's quiver without socket?

I remember last year when GGG did the reveal of the mercenary, they showed we could socket ?oils? into the quiver... but the Early Access doesn't show or talk about it at all.

Has GGG dropped that idea, or it is a thing we need to unlock much later into the game? (I suppose this has been talked about before, maybe I'm just late to the news?)

ty

Wow absolutely no one? Ok...

Merry christmas anyway. :)