Grand Theft Auto IV (GTA IV) version is a specific update for the Complete Edition on PC, which includes the main game and both Episodes from Liberty City expansions.
While various "free download" blog posts and repacks (like those from DODI Repack or FitGirl Repacks) circulate online, these are unofficial third-party distributions. The official way to obtain this version is through authorized digital storefronts. Official Details for v1.2.0.43
: Rockstar updated this edition to no longer strictly require the Social Club application to run the game.