In a statement sent to PC Gamer, Rockstar revealed that OpenIV allowed the creation of malicious mods that allowed harassment of players and that could interfere with the GTA Online experience. The publisher has yet to comment on the matter, but GTA series developer Rockstar Games revealed why this happened.
The other day, it's been reported that the lead developer of the Grand Theft Auto modding tool OpenIV, which also allowed the creation of single player mods for Grand Theft Auto V, received a cease and desist from Take-Two Interactive.