DOOM version 1.10 (what is it?)

So I've been away from my ps4 for a month or so waiting for a controller to arrive after I broke my old one, and when I switched it on, I saw there was an update for DOOM. I start downloading it, but it takes like, 10 hours to download (it's still downloading right now). I tried looking up what was in this update, but I can't find any references to DOOM ps4 version 1.10 online past one unanswered forum post. It's 18.864 gb and I don't know what it is? I know I'm probably freaking out over nothing, but if someone could just put my mind at rest I'd appreciate it...