Anthropic
claude-sonnet-4-5-latest model retirement
Stops workingSubscribe to AnthropicShare
On November 30, 2026, model claude-sonnet-4-5-latest will be retired. Calls made using this model will fail after that day. The deprecation was announced on September 30, 2026.
The error you get from November 30, 2026
What Anthropic answers a call to claude-sonnet-4-5-latest once the model is gone, as recorded from real responses:
{"type":"error","error":{"type":"not_found_error","message":"model: claude-sonnet-4-5-latest"}}What to use instead of claude-sonnet-4-5-latest
Move to claude-sonnet-5-5, which is recommended by Anthropic.
In Anthropic's words
API model name: claude-sonnet-4-5-20250929; Current state: Deprecated; Deprecated: September 30, 2026; Tentative retirement date: November 30, 2026
Facts
- API
- Anthropic
api.anthropic.com - Model
claude-sonnet-4-5-latest- Kind
- Model retirement
- Announced
- September 30, 2026
- Takes effect
- November 30, 2026
- Calls after that day
- Fail
- Source
- Deprecations page
- Last updated
- Verified
- , against Anthropic's own pages
Questions
When does claude-sonnet-4-5-latest shut down?
Calls to the model claude-sonnet-4-5-latest on Anthropic stop working on November 30, 2026.
What happens to calls after November 30, 2026?
They fail from that day.
What error does claude-sonnet-4-5-latest return once it is shut down?
Anthropic answers HTTP 404: "model: claude-sonnet-4-5-latest". 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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Is your code calling this?
Okapi finds the calls this change hits in your repo and opens the pull request with the fix before November 30, 2026.