Claude API Ships First New Version Since 2023 with Breaking Changes

Anthropic released Claude API version 2026-10-21, its first since 2023, removing temperature/topp/topk sampling parameters and causing 400 errors for some usages, alongside major SDK updates and a three-step migration guide.

2026-10-22 ~ 2026-10-22 · 3 related posts

• Anthropic ships first Claude API version since 2023: 2026-10-21 — ClaudeDevs · 2026-10-22
• Claude API 2026-10-21 removes temperature/top_p/top_k, breaks citations — ClaudeDevs · 2026-10-22
• Anthropic SDKs and ant CLI default to new 2026-10-21 API version — ClaudeDevs · 2026-10-22