Released in October 2004, this is the "holy grail" for many purists. Version 1.0 is famous for containing the "Hot Coffee" files—leftover code from a cut sexual content mini-game that was disabled but not removed from the game disc. This version is highly prized for modding because the code is less encrypted, and it is the standard for many speedrun categories. However, it is also the buggiest.
Released shortly after launch, v1.01 fixed some progression-blocking bugs, such as the "Mad Dogg" glitch where a mission could become impossible to complete. It also began the process of locking down the game files, making them harder to modify.
The DNA of V1.03 is still alive today. When Rockstar released Grand Theft Auto: The Trilogy – The Definitive Edition in 2021, the codebase was a disaster. But for years, the mobile ports and the PS4 emulated version of San Andreas used V1.03 as their base.