REPORTED DEVELOPMENT
OpenAI documentation schedules 23 October retirement for models including GPT-3.5 Turbo, certain legacy GPT-4 models, gpt-4o-2024-05-13, gpt-4.1-nano, o1, o3-mini, earlier reasoning versions, gpt-image-1 and specified fine-tuned families. The announcement dates to 22 April; the update is reaching the deadline.
The official page still lists scheduled retirements. No direct API response test established actual shutdown. Not all GPT-4o versions are affected: some later versions have a separate 14 January 2027 deadline.
WHY IT MATTERS TO THE MARKET
Exact configured model identifiers determine migration requirements; a family name alone is insufficient to establish exposure.