The original 1.0.0.0 launch version of GTA 4 was notoriously buggy and unoptimized. Version 1.0.4.0 fixes many of these issues, offering a much more stable experience while still allowing the modding freedom that was later restricted. 3. Less "Locked"

Many of the most iconic GTA 4 mods (especially ENB series, ASI loaders, and script hooks) were developed between 2009 and 2011. They were optimized specifically for the 1.0.4.0 or 1.0.7.0 patches. Using these mods on the latest 1.20 (Complete Edition) often results in crashes, missing textures, or script errors. 2. Improved Performance (Compared to 1.0.0.0)

Adjustments based on the detected operating system to improve stability.