As of August 31, 2026, GPT-5.4 and GPT-5.4 mini are no longer available in Codex for users signed in with ChatGPT. OpenAI's recommended replacements are gpt-5.6-terra and gpt-5.6-luna. Both retiring models remain on the OpenAI API and in Codex sessions authenticated with an API key. Teams should update workspace defaults, custom agents, and scheduled tasks pinned to the old IDs.

Key Takeaways

  • ✓ChatGPT-signed-in Codex drops GPT-5.4 and GPT-5.4 mini today in favor of GPT-5.6 Terra and Luna.
  • ✓API-key Codex sessions and the OpenAI API keep access to the retiring models.
  • ✓Update workspace defaults, custom agents, and scheduled tasks before they fail on pinned model IDs.
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