Splatoon 2 is getting an update ahead of the final Splatfest. The update will go live tonight, and bumps the game up to Version 4.9.0. This update will include a number of bug fixes, as well as weapon balancing. We'll provide you the full patch notes once the update is live.
We also learned that Version 5.0.0 is coming sometime in July 2019. This update will include Turf War (Splatfest) mode for Private Battles.