claude-sonnet-4-5-20250929 retirement date and replacement

Name: claude-sonnet-4-5-20250929 retires (Claude API)
Start: 2026-09-29
End: 2026-09-29

Claude API · Model · not sooner than Sep 29, 2026

Dates

Checked Sep 28, 2026 on Anthropic's page

Not sooner than	Sep 29, 2026 (not sooner than)The earliest date the vendor gives for a current model; the real date is announced later.
Replacement	None named
Model page	claude-sonnet-4-5 on Models
What it is	claude-sonnet-4-5-20250929 stopped answering on Claude API.
Source	platform.claude.com/docs/en/about-claude/model-deprecations

Claude APIModel

Stopped answering on Claude API.

not sooner thanOct 15