Anthropic's Claude Platform release notes cover recent updates including the launch of Claude Sonnet 5.5 and Claude Opus 5.5, deprecation of Claude Sonnet 4.5 with retirement from the Claude API scheduled for November 30, 2026, and Admin API methods moving out of beta in the latest SDK releases (Python 1.10.0, TypeScript 0.130.0, C# 12.52.0, Go 1.77.0, Java 2.67.0, PHP 0.53.0, Ruby 1.75.0, ant CLI 1.37.0). Code written for Claude Sonnet 5 can break on Sonnet 5.5 in five documented ways, including forced tool use returning 400 errors and changed thinking behavior.
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What to doIf you use Claude Sonnet 4.5, migrate to Claude Sonnet 5.5 before the November 30, 2026 retirement, and review the migration guide for breaking changes.
- Provider
- Anthropic
- Source
- platform.claude.com