Anthropic
claude-sonnet-4 model retirement
Stopped workingSubscribe to AnthropicShare
On June 15, 2026, model claude-sonnet-4 was retired. Calls targeting this model fail since that date. The deprecation was initially announced on April 14, 2026.
The error you get
What Anthropic answers a call to claude-sonnet-4 once the model is gone, as recorded from real responses:
{"type":"error","error":{"type":"not_found_error","message":"model: claude-sonnet-4"}}What to use instead of claude-sonnet-4
Move to claude-sonnet-5-5, recommended by Anthropic.
In Anthropic's words
API model name: claude-sonnet-4-20250514; Current state: Retired; Deprecated: April 14, 2026; Tentative retirement date: June 15, 2026
Facts
- API
- Anthropic
api.anthropic.com - Model
claude-sonnet-4- Released
- May 22, 2025 (models.dev)
- Kind
- Model retirement
- Announced
- April 14, 2026
- Takes effect
- June 15, 2026
- Calls after that day
- Fail
- Source
- Deprecations page
- Last updated
- Verified
- , against Anthropic's own pages
Questions
When does claude-sonnet-4 shut down?
Calls to the model claude-sonnet-4 on Anthropic stopped working on June 15, 2026.
What happens to calls after June 15, 2026?
They have failed since June 15, 2026.
What error does claude-sonnet-4 return once it is shut down?
Anthropic answers HTTP 404: "model: claude-sonnet-4". Send another model to fix it.
When was claude-sonnet-4 released?
claude-sonnet-4 was released on May 22, 2025, according to models.dev.
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.
claude-sonnet-4 on other APIs 1
-
No date
OpenCode
claude-sonnet-4Model retirement Deprecated, no date
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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.