It basically fixes some crashes caused by missing audio/image files! So yeah, better download that one until a real fix comes by the Devs. And no, do not download both! However, I think it won't fix the lag (The game has some annoying lag spikes during the main map exploration and saving later on due to how many ASSETS are crammed into this game! I don't know how to avoid those!)
BaasB Why didn't you simply upload the bad files instead of the whole game?! Please think of people like me who download at 400KB/s as max download speed.