Claude Releases New API Version (2026-10-21), Disables Parameters Like Temperature
Anthropic released Claude API version 2026-10-21, its first official update since 2023. The new version removes `temperature`, `top_p`, and `top_k`; passing them will return a 400 error. SDKs and the ant CLI now default to the new version, with the auth header changed to `Authorization: Bearer`. The old 2023-06-01 version remains in use.
Claude released a new API version (2026-10-21), disabling parameters such as temperature.
Anthropic has released version 2026-10-21 of the Claude API, marking the first official version update since 2023. The new version removes temperature, top_p, and top_k; attempting to pass these parameters will result in a 400 error.
The SDK and ant CLI have switched to the new version by default, and the authentication header has been changed to Authorization: Bearer. The old version (2023-06-01) has not been deprecated.
Source: ClaudeDevs(@ClaudeDevs) | Claude Platform Docs
