Official Dota 2 client via Steam; Tournament lobby hosted on Valve servers or tournament-provided dedicated servers; No third-party overlays, assistive software, or unauthorized modifications
Why people argue about this
People often assume that using a third-party overlay is just about aesthetics, so they argue it shouldn't matter for tournament play. In reality, the official Dota 2 client via Steam is crucial because it ensures all players are on an equal footing with the same in-game settings and patches, which can significantly affect gameplay strategy and balance.
