The primary reason to stick with 1.5.97 is the . Many advanced mods that change the game engine’s behavior were never updated for 1.6+. By keeping your Creation Kit pinned to the 1.5.97 environment, you ensure that any mods you create or edit remain compatible with the most stable version of the SKSE (Skyrim Script Extender) library. If you tell me what you're planning to build: Compatibility fixes for existing mods New locations or interior cells Scripted quests and NPCs

Because official support for version 1.5.97 has ended, you must manually acquire and patch the CK to ensure compatibility: