OpenAI model churn tests contracts
- OpenAI’s own help pages show ChatGPT retired GPT-4o, GPT-4.1, o4-mini, and GPT-5 variants on February 13, 2026, while API access stayed intact. - The sharpest detail is the split contract: ChatGPT lost those named models immediately, but Business, Enterprise, and Edu kept GPT-4o in Custom GPTs until April 3. - That matters because newer high-capability releases are also gated — GPT-5.5 API access is still pending, and cyber-tuned models are restricted to vetted defenders.
OpenAI is showing, pretty plainly now, that “the model you use” is not one thing. There is the ChatGPT product surface. There is the API. And there are special-access programs layered on top. Those can move on different clocks. That sounds like a product detail, but for companies building on top of OpenAI, it is basically a contract problem. ### What actually changed? On OpenAI’s help pages, the company says that as of February 13, 2026, several named models were retired from ChatGPT: GPT-4o, GPT-4.1, GPT-4.1 mini, OpenAI o4-mini, and GPT-5 in its Instant and Thinking variants. But the same notices say API access remained unchanged. That is the key split — the consumer and workspace interface changed first, while the developer surface did not. ### Why is that a bigger deal than a rename? Because a lot of teams quietly treat model names as stable infrastructure. They wire prompts, evals, latency expectations, and approval workflows to a specific label. If that label disappears from ChatGPT but still exists in the API, then “OpenAI supports this model” stops being a simple yes-or-no question. Support depends on where you access it. ### Didn’t some customers keep legacy access? Yes — but only in a narrow way. OpenAI says Business, Enterprise, and Edu customers kept access to GPT-4o inside Custom GPTs until April 3, 2026, even after the broader ChatGPT retirement. That is another signal that availability is being managed by product lane, not just by model family. Same underlying provider, different rules depending on workflow. ### What about the newest models? The same pattern shows up at the frontier end. OpenAI’s GPT-5.5 rollout page says GPT-5.5 and GPT-5.5 Pro are rolling out in ChatGPT and Codex, but
