Those are the patch notes:
Season 1 of Ranked Battles will kick off, allowing you to enjoy Ranked Battles through the Battle Stadium.
Please check the in-game notice for more details about Ranked Battles Season 1.
An issue has been fixed that caused the music to not play correctly during the battles with the Elite Four and the Top Champion in the Victory Road path.
Other select bug fixes have been made.
We are aware that players may encounter issues that affect the games’ performance. Our goal is always to give players a positive experience with our games, and we apologize for the inconvenience. We take the feedback from players seriously and are working on improvements to the games.
Game Freak is aware that players are experiencing bad frame rates, glitches, etc. my question is how the game runs after this update.