put
https://app.customgpt.ai/api/v1/projects//settings/persona-activate/
Activates a previous persona version, making it the current active persona. This creates a new version entry in the history (it doesn't overwrite), preserving the full audit trail. Use this to roll back to a known-good configuration.
Notes: Requires Custom plan.
Warning: This doesn't delete newer versions — it creates a new entry based on the restored version.