# Anthropic API version 2026-10-21 and the SDK majors that send it

Source page: https://dev-news.anonyfox.com/anthropic/

Every anthropic-sdk-python release since 2024 from GitHub, what API version 2026-10-21 removes and renames, and the eight SDK and CLI majors released with it on 21 October.

## Where it stands (2026-10-24)

On 21 October 2026 Anthropic released API version 2026-10-21, the first new value for the anthropic-version header since 2023-06-01, 1,238 days earlier, and only the third version the API has had. The same day it published new major versions of every client SDK and the ant CLI that send it by default: Python 2.0.0, TypeScript 1.0.0, Go 2.0.0, Java 3.0.0, Ruby 2.0.0, PHP 1.0.0, C# 13.0.0 and ant 2.0.0, all now licensed under Apache 2.0 instead of MIT.

Under the new version, temperature, top_p and top_k are removed and return a 400 error on every model, as do document blocks placed directly in assistant messages and citations on text in user messages. Six Admin and Analytics API fields are renamed. On Amazon Bedrock the new version only works with Claude 4.7 and later models. The Python SDK reached 1.0.0 only on 20 August, when it moved to httpx2, and has shipped 22 releases since; Claude Code 2.1.307 added /claude-api api-version to move code to the new version.

## Latest stable releases

- [v2.3.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v2.3.0) (2026-10-23): api: add Claude Tag endpoints for Claude Enterprise organizations
- [v2.2.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v2.2.0) (2026-10-23): api: add support for message threads
- [v2.1.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v2.1.0) (2026-10-21): api: add enforcement status, actions and filter to user profiles
- [v2.0.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v2.0.0) (2026-10-21): api: add support for new API version 2026-10-21
- [v1.17.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.17.0) (2026-10-20): api: add org webhook endpoints and user profile enforcement events
- [v1.16.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.16.0) (2026-10-20): api: add datarefreshedat and hasmore to analytics report pages
- [v1.15.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.15.0) (2026-10-15): api: add betweentools to thinking types in model capabilities
- [v1.14.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.14.0) (2026-10-14): api: add executionidentity to Managed Agents agents
- [v1.13.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.13.0) (2026-10-09): api: add types for the Chat and Cowork unified analytics metrics
- [v1.12.1](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.12.1) (2026-10-08): ci: check that pull requests update the changelog
- [v1.12.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.12.0) (2026-10-07): api: add claude-haiku-5-5 and typed computer and browser toolset tool calls (f6346e6)
- [v1.11.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.11.0) (2026-09-30): api: add list spend limits endpoint (e8f0cac)
- [v1.10.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.10.0) (2026-09-30): api: add a refusal stop reason and stopdetails to Managed Agents session idle events (cba653f)
- [v1.9.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.9.0) (2026-09-28): api: add betweentools thinking type (a9a577d)
- [v1.8.0](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.8.0) (2026-09-22): api: add support for claude-opus-5-5, inline tool definitions and MCP tool-list pinning (beta) (b5cc700)

## In the dev-news log

- **anthropic 2.2.0 and 2.3.0** (2026-10-23). 2.2.0 adds message threads and usage and cost reports by dimension, marking the older reports legacy. 2.3.0 adds Claude Tag endpoints for Enterprise organizations. That makes six stable releases between 20 and 23 October. [log](https://dev-news.anonyfox.com/log/2026-10-23/#anthropic-3)
- **anthropic 2.0.0** (2026-10-21). The only breaking entry is support for API version 2026-10-21. 1.0.0 shipped on 20 August, so that is two majors in 62 days. 2.1.0 followed the same day. [log](https://dev-news.anonyfox.com/log/2026-10-21/#anthropic-3)
- **anthropic 1.16.0 and 1.17.0** (2026-10-20). Two minors on one day. 1.16.0 makes User Profiles generally available; 1.17.0 adds org webhook endpoints and user profile enforcement events. [log](https://dev-news.anonyfox.com/log/2026-10-20/#anthropic-1)

Releases since 2024: 202 stable, 0 prereleases. JSON: https://dev-news.anonyfox.com/anthropic.json. Feed: https://dev-news.anonyfox.com/anthropic/feed.xml