o1 changelog

Legacy GPT, o-series and GPT Image 1 snapshots shut down on October 23

OpenAI shut down the legacy snapshots it announced on April 22, 2026, on October 23, 2026. They include gpt-3.5-turbo, gpt-4, gpt-4-turbo, gpt-4.1-nano, gpt-image-1, o1, o1-pro, o3-mini, o4-mini and gpt-4o-2024-05-13, plus several fine-tuned versions.

Who is affected:

Anyone still calling these models in the API now gets errors.

Action needed:

Switch to gpt-5.6-sol, gpt-5.6-terra, gpt-5.6-luna, or gpt-image-2.5-sunburst or gpt-image-2.5-flare as listed on the page.

Legacy GPT, o-series and gpt-image-1 snapshots to shut down October 23, 2026

OpenAI announced that gpt-3.5-turbo, gpt-4, gpt-4-turbo, gpt-4.1-nano, gpt-4o-2024-05-13, gpt-image-1, o1, o1-pro, o3-mini and o4-mini (plus several fine-tuned bases) shut down on October 23, 2026. Substitutes are GPT-5.6 Sol, Terra or Luna and GPT Image 2.5.

Who is affected:

Apps calling any of these snapshots or fine-tunes built on them.

Action needed:

Migrate before October 23, 2026 to the listed GPT-5.6 or GPT Image 2.5 substitute.