Anthropic retired Claude Opus 4.1 on August 5, 2026
Anthropic confirms that claude-opus-4-1-20250805 retired on August 5, 2026 and Claude API requests return an error. Its retirement release note recommends Claude Opus 5, while its current deprecation table recommends claude-opus-4-8; the recommended replacement is inconsistent across official sources.
Required action
Remove the retired exact ID from production configuration. Validate a currently available replacement against your platform, access and workload; do not present either conflicting recommendation as the single official answer.
Scope and evidence limits
Claude API, Claude Platform on AWS and Microsoft Foundry; partner-operated platform schedules differ
This date applies to Anthropic-operated platforms. Bedrock and Google Cloud schedules may differ.
not_tested
Official sources
Affected components
claude-opus-4-1-20250805 on the Claude API
Affected users
Claude API customers whose applications still call the dated Opus 4.1 model ID.
Migration guidance
Official recommendations conflict: the August 5 release note names Claude Opus 5; the current deprecation table names claude-opus-4-8. Validate a currently available replacement for your platform and workload.
Correction history
- 2026-08-23: Post-deadline verification changed the record from scheduled retirement to retired and unavailable.
- 2026-09-21: Current live wording treats Opus 5 as unambiguous official guidance. Anthropic confirms that claude-opus-4-1-20250805 retired on August 5, 2026 and Claude API requests return an error. Its retirement release note recommends Claude Opus 5, while its current deprecation table recommends claude-opus-4-8; the recommended replacement is inconsistent across official sources.