Version 1.0 (the "Day 1" retail release) is the gold standard for mods. Popular multiplayer clients like SA-MP (San Andreas Multiplayer) and MTA (Multi Theft Auto) often require this specific version to function correctly.
Grand Theft Auto: San Andreas (Retail Edition) - Internet Archive gta san andreas pc internet archive
The Internet Archive hosts several iterations of the game, each serving a different purpose for researchers and enthusiasts: Internet Archivehttps://archive.org Version 1