Halo 5 must have 4-player splitscreen. However, it does not have to have 4-player splitscreen for all game modes. Halo 5 only needs 4-player splitscreen for local Custom Games and Online Matchmaking (regular Online Matchmaking, I know in Halos with 4-player splitscreen Grifball only allows 2-player splitscreen, and other Multiplayer game modes do not allow splistscreen at all. But in Halos with 4-player splitscreen, Team Slayer and Big Team Battle could have 4 player-splitscreen). Halo 5 does not need to have 4-player splitscreen for modes such as Campaign, Firefight, or specific Matchmaking modes.