CitizenMP:IV is a multiplayer modification for the 2008 PC port of Grand Theft Auto IV, which differs from other multiplayer modifications in that it doesn't reimplement networking frameworks, but builds upon the powerful framework by the Rockstar Studios, as also used in Max Payne 3 and Grand Theft Auto V.
StreamingCitizenMP:IV allows servers to use custom cars, maps, weapons, and more.
AICitizenMP:IV allows servers to keep the original game AI, so you'll never be alone. You can also PvE!
Sync qualityCitizenMP:IV uses the original multiplayer network code with improvements, so you'll have the best sync around.