OpenAI Retires o3 and GPT-4.5: Complete Model Deprecation Timeline and Migration Guide
In a major update announced in June 2026, OpenAI has officially confirmed the retirement of its o3 and GPT-4.5 language models. This move marks a significant shift in OpenAI’s model lineup, consolidating focus on the newer GPT-5.5 and GPT-5.5 Instant models. Developers and enterprises using the retired models must adapt…
