Anthropic · Model retirement
claude-sonnet-4-5-20250929
Stops working (in 39 days)
Calls to the model claude-sonnet-4-5-20250929 on Anthropic stop working on November 30, 2026.
What to use instead of claude-sonnet-4-5-20250929
Move to claude-sonnet-5-5, recommended by Anthropic.
Facts
- API
- Anthropic
api.anthropic.com - Model
claude-sonnet-4-5-20250929- Kind
- Model retirement
- Announced
- September 30, 2026
- Takes effect
- November 30, 2026
- Calls after that day
- Fail
- Source
- Deprecations page
- Last updated
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