Anthropic · Model retirement
Claude Sonnet 4.5 deprecated
Anthropic notified API developers that Claude Sonnet 4.5 retires on November 30, 2026, with Claude Sonnet 5.5 as the recommended replacement.
- Occurrence
- Occurrence date basis
- Provider publication date
- Effective date
- Status recorded with this event
- scheduled
- Event checked
Original sources
- Model deprecations - Claude Platform Docs (opens in a new tab) ↗
First-party source · Source checked
2026-09-30: Claude Sonnet 4.5 model On September 30, 2026, Anthropic notified developers using Claude Sonnet 4.5 of its upcoming retirement on the Claude API. Retirement date November 30, 2026 claude-sonnet-4-5-20250929 claude-sonnet-5-5
Recording provenance
First recorded by StackReplay . This is a discovery date, not the occurrence date.
Event ID: claude-sonnet-4-5-deprecated