Question about DLC

I have the game on PS4, but I haven't played in a while. Of course now I have a freaking 20 GB update. I just wanted to play the episode Prompto. I bought it and installed it, but it's not showing up in the downloadable content section. Do you have to update in order to play the dlc? That's pretty ridiculous if that's the case. My storage is already full as it is. 20gb is like a full game and it's gonna take forever.