Mostly to shore up the campaign
Walking through the patch, it mostly impacts some last-minute campaign changes, also referred to as “hero mode.” You can alter Cap’n Cuttlefish’s appearance in-game, and utilize a photo mode “in some places” in the story. The patch also enables online play for folks to get the game ready for launch on September 9 worldwide.
Simple stuff! Thankfully it’s not a massive patch that fixes crucial issues. I was able to play through the entire campaign, as well as a number of turf war, ranked, salmon run, and Tableturf Battle (the new card game) without any big problems. Ideally, this patch doesn’t add any!