Warning: If you download an old update (e.g., v1.0.1), you will miss the Pier of the Unknown compatibility patches, rendering the DLC unplayable.
Cassette Beasts on Nintendo Switch: Technical Overview, Updates, and DLC Cassette Beasts ROM NSP UPDATE DLC - Switch Game
It was waiting for him to decide what the next patch would fix. Warning: If you download an old update (e