Deprecation

OpenAI Retires GPT-4o Early. Its Replacement Rejects Temperature.

On 14 October OpenAI told developers that GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini leave the API on 14 January 2027, 92 days later, while the same deprecations page promises generally available models at least six months of notice and gives no reason for the shorter window. The replacement named for all four is gpt-6-luna at $0.10 and $0.50 per million tokens, a reasoning model that defaults to medium effort: swapping the model ID into a GPT-4o-style Chat Completions call returns a 400 for temperature, a 400 for a function tool and a 400 for max_tokens until reasoning_effort is set to none, and at its default it costs more per call than GPT-4o mini on a one-word classifier. Fine-tuned versions die the same day, new fine-tuning jobs end on 6 January, Luna cannot be fine-tuned, Predicted Outputs is left with no model, and Azure runs the same snapshots until 14 April 2027.