Compatibility basics
Skyrim Special Edition version 1.6.640 (often referred to as the Anniversary Edition update), you must use SKSE version 2.2.3 skyrim+skse+16640+2021
: Players began frantically blocking Steam updates and "downgrading" their game files just to keep their characters from crashing on startup. The SKSE Heroics Compatibility basics
Skyrim Special Edition version 1
6.640, or are you trying to from a more recent version? skyrim+skse+16640+2021
You cannot use .NET Script Framework. You must find alternative mods. For grass caching, you now need Grass Cache Fixes (which uses ConsoleUtilSSE NG) instead of No Grass in Objects.