# OpenAI o1 — deprecation status

> Yes — OpenAI deprecated o1 on April 22, 2026 and shuts it down on October 23, 2026 (in 85 days). The recommended replacement is GPT-5.6 Sol.

The first generally available reasoning model, and the release that proved spending inference compute could substitute for a larger model. It introduced the constraints the whole o-series inherited: no system messages at launch, no streaming, and max_completion_tokens in place of max_tokens.

## Facts

| Field | Value |
| --- | --- |
| Provider | OpenAI |
| Model id | `o1` |
| Status | Deprecated |
| Aliases | `o1-2024-12-17` |
| Released | December 17, 2024 |
| Deprecated | April 22, 2026 |
| Shutdown | October 23, 2026 (in 85 days) |
| Last verified | July 30, 2026 |

## Replacement

- **GPT-5.6 Sol** (`gpt-5.6-sol`) · recommended — https://modeldeprecations.dev/openai/gpt-5.6-sol
  - Sol lifts most of o1's restrictions — system messages, streaming and tool calls all work — so code written defensively around o1 can usually be simplified rather than ported.
  - Parameters it accepts: https://modelparams.dev/models/openai/gpt-5.6-sol

```diff
- "model": "o1"
+ "model": "gpt-5.6-sol"
```

## FAQ

### When will OpenAI o1 shut down?

OpenAI o1 is scheduled to shut down on October 23, 2026, in 85 days.

### What replaces OpenAI o1?

OpenAI recommends GPT-5.6 Sol (`gpt-5.6-sol`) as the replacement for OpenAI o1. Sol lifts most of o1's restrictions — system messages, streaming and tool calls all work — so code written defensively around o1 can usually be simplified rather than ported.

### Is OpenAI o1 still available?

Yes, for now. OpenAI o1 is deprecated but still answers requests until October 23, 2026. Deprecated models get no further updates and are the first to lose capacity.

### How do I migrate from OpenAI o1 to gpt-5.6-sol?

Swap the model id in your API call: replace "o1" with "gpt-5.6-sol". Sol lifts most of o1's restrictions — system messages, streaming and tool calls all work — so code written defensively around o1 can usually be simplified rather than ported.

### Does this apply to o1-2024-12-17 too?

Yes. OpenAI o1 is also published as `o1-2024-12-17`; that id shares the same lifecycle dates as `o1`.

## Sources

- [OpenAI API deprecations](https://developers.openai.com/api/docs/deprecations) — accessed 2026-07-30

---

Canonical page: https://modeldeprecations.dev/openai/o1
JSON: https://modeldeprecations.dev/api/v1/models/openai/o1.json