CriticalDeprecation
Anthropic retiring 1M token context window beta for Claude Sonnet 4
Action Required
Applications relying on the 1M token context window will fail to function correctly after April 30, 2026, necessitating immediate migration to a supported model.
AI Impact Summary
Anthropic is retiring the 1M token context window beta for Claude Sonnet 4.5 and 4, with a final sunset date of April 30, 2026. Users relying on this beta feature must migrate to Claude Sonnet 4.6 or Claude Opus 4.6 to continue utilizing the full 1M token context window at standard pricing. This change impacts applications that heavily rely on extended context for tasks like long-form content generation or complex reasoning, requiring immediate planning for migration.
Anthropic retiring 1M token context window beta for Claude Sonnet 4
Affected Systems
Claude Sonnet 4
- Date
- 30 Apr 2026
- Change type
- deprecation
- Severity
- critical