We've retired the Claude Sonnet 4 model and the Claude Opus 4 model

Monday, 15 June 2026

AI summary

Written by AI from the official notes. Check them for exact details.

The Claude Sonnet 4 and Claude Opus 4 models have been retired and are no longer accessible.

Claude Sonnet 4 model retired, requests return error.
Claude Opus 4 model retired, requests return error.
Upgrade recommended to Claude Sonnet 4.6 and Claude Opus 4.8.
Ongoing access for researchers available through External Researcher Access Program.

Why it matters: Users of the Claude models should upgrade to the latest versions to avoid errors.

We've retired the Claude Sonnet 4 model (claude-sonnet-4-20250514) and the Claude Opus 4 model (claude-opus-4-20250514). All requests to these models on the Claude API will now return an error. We recommend upgrading to Claude Sonnet 4.6 and Claude Opus 4.8 respectively. Researchers can request ongoing access through the External Researcher Access Program.