Claude API changelog

API version 2026-10-21 removes temperature, top_p and top_k

Anthropic released API version 2026-10-21 and new major SDK versions that send it by default. Under this version, temperature, top_p and top_k return a 400 error for every model, and the SDKs move from the MIT License to Apache 2.0.

Who is affected:

Any app that upgrades to the new SDK majors (Python 2.0.0, TypeScript 1.0.0 and others).

Action needed:

Remove sampling parameters before upgrading the SDK, or pin the older API version.

Python SDK v1.0 removes sampling parameters and the Text Completions API

Version 1.0 of the Anthropic Python SDK requires Python 3.10 or later and removes the legacy Text Completions API and the temperature, top_p and top_k parameters on Messages methods.

Who is affected:

Python apps that upgrade the anthropic package to 1.0.

What to do:

Follow the v1 migration guide before upgrading the Python SDK.