Mistral
magistral-small-2509 model retirement
Stopped workingSubscribe to MistralShare
Mistral retired model magistral-small-2509 on July 31, 2026. Calls to this model fail since that date. The change took effect following an announcement on April 30, 2026.
The error you get
What Mistral answers a call to magistral-small-2509 once the model is gone, as recorded from real responses:
{"object":"error","message":"Invalid model: magistral-small-2509","type":"invalid_model","param":null,"code":"1500"}What to use instead of magistral-small-2509
Mistral recommends migrating to Mistral Small 4.
Facts
- API
- Mistral
api.mistral.ai - Model
magistral-small-2509- Kind
- Model retirement
- Announced
- April 30, 2026
- Takes effect
- July 31, 2026
- Calls after that day
- Fail
- Source
- Lifecycle page
- Last updated
- Verified
- , against Mistral's own pages
Questions
When does magistral-small-2509 shut down?
Calls to the model magistral-small-2509 on Mistral stopped working on July 31, 2026.
What happens to calls after July 31, 2026?
They have failed since July 31, 2026.
What error does magistral-small-2509 return once it is shut down?
Mistral answers HTTP 400: "Invalid model: magistral-small-2509". Send another model to fix it.
How do I find the calls this hits in my code?
Okapi reads your repository, finds the calls this change hits and opens a pull request with the fix. It never commits to your branches: every change comes as a pull request you review.
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You fixed this one by hand.
Okapi opens the pull request with the fix before the next breaking change reaches your code.