If your GTA V is currently on game version 1.0.2699.0, then downloading Script Hook V 2699 is for modding. Without it, no script mods will function.
"Supports GTA V [1.0.2699.0] (patch 1.69)" script hook v 2699 download
When looking for modding tools, safety is paramount. The internet is rife with fake download sites that bundle malware with popular modding files. It is highly recommended that you only download Script Hook V from the official source. If your GTA V is currently on game version 1
Some specific mods or complex scripts may not yet be updated for the very latest game version. Stability: script hook v 2699 download