Is there a way to revert to the old HUD

Looking on Twitch, the majority of streamers seem to still have the old HUD. I wouldn't think it would just be an overlay because the overlay just changes the skin right? There are a handful of streamers that seem to be showing the new HUD but the vast majority are seeming to have the old style HUD. It made me hope there is a way to revert to the old one.. Anyone? -edited- I wanted to add, it seems the mini map most are using is the new one . Everything else seems to be from the old HUD..