Published October 15, 2026 · AI News
OpenAI told developers on October 14, 2026 that it will remove GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini from its API on January 14, 2027. Its recommended replacement for all four is GPT-6 Luna. Fine-tuned versions of those models shut down on the same day.
The same day, OpenAI also retired GPT-5.5 from Codex for people who sign in with a ChatGPT account. They are pointed to GPT-6.1 Sol instead.
What changed
| Model (API) | Shutdown date | Replacement |
|---|---|---|
| GPT-4o (2024-08-06, 2024-11-20) | January 14, 2027 | GPT-6 Luna |
| GPT-4o mini (2024-07-18) | January 14, 2027 | GPT-6 Luna |
| GPT-4.1 (2025-04-14) | January 14, 2027 | GPT-6 Luna |
| GPT-4.1 mini (2025-04-14) | January 14, 2027 | GPT-6 Luna |
| GPT-5.5 in Codex (ChatGPT sign-in) | October 14, 2026 | GPT-6.1 Sol |
OpenAI’s notice covers the API only. It says nothing about the ChatGPT app, and API-key sessions in Codex are not affected by the GPT-5.5 change.
What it means for you
If you only chat in ChatGPT, you do not need to do anything. This hits people and companies who built tools on top of OpenAI’s API: customer-support bots, writing plug-ins, internal apps and automations.
- Check your apps and plug-ins. Many older tools still call
gpt-4oorgpt-4o-miniby name. After January 14 those calls will fail. - Test before you switch. OpenAI says GPT-6 Luna has lower per-token pricing, but total cost depends on how many tokens your workload uses. Run real samples first, and check output formats and tool calls.
- Fine-tunes need a plan. A fine-tuned GPT-4o model will stop working on the same date. Budget time to rebuild it on a newer model.
- Codex users: update saved model settings, scripts and scheduled tasks that still pick GPT-5.5.
For Canadian businesses, three months is short if a vendor owns the integration. Ask your software providers now which model they call, and get a date in writing. Remember that OpenAI API bills are charged in US dollars.