# clm_D1A09315FDBF

subject: Claude (/record/claude.md)  
predicate: model_release  
value: Claude Sonnet 5.5  
valid_from: 2026-09-28  
valid_to: null  
published: 2026-09-28  
recorded: 2026-10-31  
confidence: 0.70  
status: valid  
assertable: true  
superseded_by: null  
last_updated: 2026-10-31  
checked: 2026-10-31 · its source page states the value and the date  

> September 28, 2026 Claude Sonnet 5.5 launch We just launched Claude Sonnet 5.5, the second model in our Claude 5.5 family.

What https://support.claude.com/en/articles/12138966-release-notes#2026-09-28 says, word for word.

## Sources

- https://support.claude.com/en/articles/12138966-release-notes#2026-09-28 (primary, Anthropic, published 2026-09-28)

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