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Anthropic releases Claude API version 2026-10-21, which is the first official version release since 2023; version 2023-06-01 is not deprecated. This version removes temperature, top_p, and top_k from the Messages API; documents in assistant turns and citations in user turns will return 400; some deprecated Admin and Enterprise Analytics API fields are replaced. New major versions of the Anthropic SDK and ant CLI are released the same day and use 2026-10-21 by default; you can update in Claude Code with the /claude-api skill, or handle items one by one according to the migration guide. There is currently no further evidence-backed development after this version's release.
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Latest development · Report
AI Daily: Claude Duet and GPT-6 Series in Private BetaDevelopments
1 confirmed developments
- Source:Claude Devs
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Oct 22
Testing Catalog
AI Daily: Claude Duet and GPT-6 Series in Private Beta
Anthropic has opened the waitlist for Claude Duet, a standalone proactive agent app built on Claude Opus 5.5, aimed at Pro and Max users in the US. OpenAI's GPT-6 Astra, GPT-6.1 Sol, GPT-6 Luna and Codex workflows are in private preview on Google Cloud Model Garden. Recursive released Flint, a 40B MoE open-source local coding model under Apache 2.0, claiming it is up to 2x faster than comparable models.
Claude DevsFirst-party
Anthropic releases Claude API version 2026-10-21
Anthropic releases Claude API version 2026-10-21, the first official version release since 2023; the 2023-06-01 version is not deprecated. This version removes temperature, top_p, and top_k from the Messages API, returns 400 for documents in assistant turns and citations in user turns, and replaces several deprecated Admin and Enterprise Analytics API fields. New major versions of the Anthropic SDK and the ant CLI are released the same day and default to 2026-10-21; you can update using the /claude-api skill in Claude Code, or adjust item by item according to the migration guide.
Claude DevsFirst-party
Anthropic releases Claude API version 2026-10-21
Anthropic releases Claude API version 2026-10-21, the first formal version release since 2023; version 2023-06-01 is not deprecated. This version removes temperature, top_p, and top_k from the Messages API; documents in assistant turns and citations in user turns will return 400; and some deprecated Admin and Enterprise Analytics API fields are replaced. New major versions of the Anthropic SDK and ant CLI are released the same day and use 2026-10-21 by default. You can update using the /claude-api skill in Claude Code, or handle items one by one according to the migration guide.