GPT-5.5 retirement in Codex: check saved model settings
The October 14 change affects ChatGPT sign-in. Check workspace defaults, custom agents and scheduled tasks; API-key sessions have a different scope.
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GPT-5.5 retired from Codex with ChatGPT sign-in on October 14, 2026, at 19:00 UTC—noon Pacific daylight time. The official model guide lists replacements and settings to review. A saved task that still selects gpt-5.5 may need a model change.
Match the replacement to your sign-in method
| Access path | Official scope and replacement |
|---|---|
| ChatGPT sign-in on Plus, Pro, Business, Enterprise or Edu | Choose GPT-6.1 Sol (gpt-6.1-sol) when available to your account and client |
| ChatGPT sign-in on Free or Go | Choose GPT-6 Luna (gpt-6-luna) in the desktop app when available |
| OpenAI API or an API-key-authenticated Codex session | This retirement does not affect this path; model access follows the API project |
Enterprise and Edu availability also depends on administrator settings. Entering a model identifier does not grant workspace access to it.
Check settings beyond the current conversation
Use the model control below the desktop composer, or /model in an interactive CLI session. If a new chat works but an older task still fails, inspect persistent choices:
- Workspace defaults and saved client model selections.
- Managed configuration and custom agents that name
gpt-5.5. - Scheduled tasks, automation scripts and launch arguments that specify a model.
A CLI launch can explicitly select a model your account already supports:
codex --model gpt-6.1-sol
This illustrates the identifier. Free, Go and workspaces without Sol access need an available alternative.
Verify the saved task too
Reopen the affected task, confirm the selected model, and try a small task that exercises the tools you need. If interactive use succeeds while an automation still reports the retired model, inspect that automation's saved settings first.
Keep sign-in method, subscription access and workspace permissions separate when diagnosing the failure. This guide reflects the official migration notice and changelog checked on October 21, 2026.