# Claude API 2026-10-21: Breaking Changes Devs Must Fix Now

> Source: <https://byteiota.com/claude-api-2026-10-21-breaking-changes-devs-must-fix-now/>
> Published: 2026-11-01 00:11:31+00:00

Anthropic’s new API version rejects temperature, top_p, and top_k with a 400 error. Python SDK 2.0 breaks MessageParam constructors. Two more changes hit November 30.

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Claude API 2026-10-21: Breaking Changes Devs Must Fix Now
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