You'll need to download a 500MB patch for Fallout 4 if you want your game to be optimised before beginning your adventure on the PlayStation 4. We reviewed the title with the update installed, as it was actually made available to download days ago.
We can't tell you the specifics of what the patch does, though. The update history on our system merely states the following: "Some last changes and optimisations for launch day". In any case, we reckon that you'll definitely want this before booting the game up for the first time. Good job it's not gigantic, eh?