OpenAI shuts down GPT-4, o1, o3-mini and o4-mini in its API

OpenAI shut down a large batch of older models in its API on October 23, 2026. The list includes GPT-3.5 Turbo, GPT-4, GPT-4 Turbo, the first GPT-4o snapshot, GPT-4.1 nano, o1, o1-pro, o3-mini, o4-mini and the gpt-image-1 image model. “Access to these models was shut down on October 23, 2026,” OpenAI’s deprecations page says. Fine-tuned versions were shut down on the same day. OpenAI first announced the removal on April 22, 2026.

What was removed, and the replacements

Model or snapshot	OpenAI’s replacement
gpt-3.5-turbo, gpt-3.5-turbo-0125	gpt-5.6-terra
gpt-4, gpt-4-0613, gpt-4-1106-preview	gpt-5.6-sol
gpt-4-turbo, gpt-4-turbo-2024-04-09	gpt-5.6-sol
gpt-4o-2024-05-13	gpt-5.6-sol
gpt-4.1-nano	gpt-5.6-luna
o1, o3-mini	gpt-5.6-sol
o1-pro	gpt-5.6-sol with reasoning.mode: pro
o4-mini (and its fine-tune)	gpt-5.6-terra
gpt-image-1	gpt-image-2.5-sunburst or gpt-image-2.5-flare

Fine-tunes of gpt-3.5-turbo, gpt-4, gpt-4.1-nano, babbage-002 and davinci-002 were also shut down. OpenAI names the matching base model above as the replacement. The page does not say what error an API call to a removed model now returns.

What the replacements cost

On OpenAI’s pricing page on October 26, 2026, standard prices per 1M tokens are $4 input and $20 output for gpt-5.6-sol, $2 and $12 for gpt-5.6-terra, and $0.20 and $1.20 for gpt-5.6-luna. The Sol price is a promotion that OpenAI says runs “at least through November 21, 2026”; the page does not give the regular price after it. The newer gpt-6-luna lists at $0.10 and $0.50, and gpt-6.1-sol at $2 and $10. You can compare these on our AI model price comparison and estimate a bill with the token cost calculator.

More shutdowns coming

The same page lists three more dates from a June 3, 2026 notice:

• October 31, 2026: existing evals become read-only.
• November 30, 2026: the Evals dashboard and API shut down. OpenAI links a guide for moving to Promptfoo.
• November 30, 2026: the v1/prompts API and reusable prompt objects shut down, and so does Agent Builder. ChatKit stays available.

What to do

If anything still calls one of these model IDs, it no longer works. Search your code, config and usage dashboard for the IDs in the table, switch to a replacement, and test output and cost per task. If you use Evals, saved prompts or Agent Builder, follow OpenAI’s migration guides before November 30; the page does not say what happens to stored evals, prompts or agents after that.