OpenAI notified developers on October 14 that specified GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini models will be removed from its API on January 14, 2027. Fine-tuned versions built on those models share the same deadline.

OpenAI recommends GPT-6 Luna as the replacement for the retiring models. Its migration guidance tells developers to test representative workloads, check output formats and tool use, and move production traffic over gradually rather than swapping the model name blind.

The notice gives developers about three months, which drew criticism because OpenAI had previously talked about longer deprecation windows. A separate, sooner batch of older snapshots is already due to stop serving on October 23, so teams with legacy model names in production have two deadlines to check.