Model retirements / GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini
GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini retire on 14 Jan 2027.
OpenAI removes gpt-4o (2024-08-06 and 2024-11-20), gpt-4o-mini, gpt-4.1 and gpt-4.1-mini on 14 January 2027. The replacement for all of them is gpt-6-luna. Source: OpenAI: deprecations, checked 8 Nov 2026.
What's retiring, and what replaces it
| Retiring | Official replacement | Our data |
|---|---|---|
gpt-4o-2024-08-06GPT-4o (2024-08-06) |
gpt-6-lunaGPT-6 Luna |
GPT-4o (2024-08-06) · GPT-6 Luna · the two compared |
gpt-4o-2024-11-20GPT-4o (2024-11-20) |
gpt-6-lunaGPT-6 Luna |
GPT-6 Luna |
gpt-4o-miniGPT-4o mini |
gpt-6-lunaGPT-6 Luna |
GPT-4o mini · GPT-6 Luna · the two compared |
gpt-4.1GPT-4.1 |
gpt-6-lunaGPT-6 Luna |
GPT-4.1 · GPT-6 Luna · the two compared |
gpt-4.1-miniGPT-4.1 mini |
gpt-6-lunaGPT-6 Luna |
GPT-4.1 mini · GPT-6 Luna · the two compared |
Fine-tuned models follow their base model's schedule, so a fine-tune of one of these goes on the same date.
Dates and replacements are OpenAI's, from https://developers.openai.com/api/docs/deprecations. Plan to have moved before the date; check the source for any change.
Why a swap can quietly change your outputs
A replacement may score higher on benchmarks, but that doesn't mean it does your task the same way. Usually nothing errors. The answers change, and your users may notice before you do.
- Format
- The new model may wrap JSON in a code fence, add Markdown, change headings or drop a field your code reads.
- Tone
- Warmer, blunter, more formal or more chatty. It reads as a different writer.
- Refusals
- It may refuse or hedge on inputs the old model handled, or answer ones it used to decline.
- Length
- Answers often get longer or shorter. That can break a limit on screen, in an SMS or in a feed.
- Instructions
- Edge-case rules in your prompt (never mention X, always end with Y) are where models differ most.
- Cost and speed
- Price per token, tokens per answer and thinking time all change, so the cost of each answer can move even at a similar list price.
Re-test before you switch
- Find every place your code, config and environment variables name the old model ID.
- Collect 10 to 20 real inputs, including the awkward ones that went wrong before.
- Write down what a good answer does: its format, length, what it must say and must not.
- Run the old and the new model on the same prompt and the same inputs, side by side.
- Read the answers that changed, not just the pass rate.
- Compare cost and time per answer, then adjust the prompt if you need to and test again.
- Switch before the date, and keep the cases as a regression test for the next change.
We can run both sides of these swaps for you: GPT-4o (2024-08-06) against GPT-6 Luna; GPT-4o (2024-11-20) against GPT-6 Luna; GPT-4o mini against GPT-6 Luna; GPT-4.1 against GPT-6 Luna; GPT-4.1 mini against GPT-6 Luna.