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Anthropic · Model retirement

claude-sonnet-4

Stopped working

Calls to the model claude-sonnet-4 on Anthropic stopped working on June 15, 2026.

What to use instead of claude-sonnet-4

Move to claude-sonnet-5-5, recommended by Anthropic.

Facts

API
Anthropic api.anthropic.com
Model
claude-sonnet-4
Kind
Model retirement
Announced
April 14, 2026
Takes effect
June 15, 2026
Calls after that day
Fail
Source
Deprecations page
Last updated

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