These act as "unlock keys" for content already present in the game's data.
The game has moved through several major version milestones (e.g., v1.0.0 to v9.0.0+), each bringing fresh gear and stages. splatoon 3 switch nsp update dlc
Splatoon is primarily an online game. You cannot participate in Turf Wars, Anarchy Battles, or Salmon Run unless your version matches the current server requirements. These act as "unlock keys" for content already