HighDeprecation
Claude Sonnet 4.5/4.0 1M token context beta retired — migrate to 4.6 models
Action Required
Applications using context windows larger than 200k tokens on Sonnet 4.5/4.0 will fail unless migrated to Sonnet 4.6 or Opus 4.6.
AI Impact Summary
Anthropic is retiring the 1M token context window beta for Claude Sonnet 4.5 and 4.0, effective immediately for the context-1m-2025-08-07 beta header. Applications relying on this beta feature will begin receiving errors when context exceeds 200k tokens. Claude Sonnet 4.6 and Claude Opus 4.6 are the only current models supporting 1M context windows, requiring immediate migration for any production workloads that depend on extended context.
Claude Sonnet 4.5/4.0 1M token context beta retired — migrate to 4.6 models
Affected Systems
Claude Sonnet 4.5
- Date
- Date not specified
- Change type
- deprecation
- Severity
- high