According to developers at Steam Community, the v1.2.3 update introduced several quality-of-life and technical improvements:
: Support for local split-screen multiplayer for up to 4 players. Slipstream - Steam Community File: Slipstream.v1.2.3.03.zip ...
: Grand Tour, Cannonball, Grand Prix, Single Race, Time Trial, and Battle Royale. According to developers at Steam Community, the v1