Claude Platform release notes — October 21, 2026, Claude Platform changelog, 21 Oct 2026

We've released API version 2026-10-21. Migrating to API version 2026-10-21 shows how to upgrade.
We've released new versions of the client SDKs and the ant CLI that send API version 2026-10-21 by default: Python SDK 2.0.0, TypeScript SDK 1.0.0, C# SDK 13.0.0, Go SDK 2.0.0, Java SDK 3.0.0, PHP SDK 1.0.0, Ruby SDK 2.0.0, and ant CLI 2.0.0. See Switch to 2026-10-21.
The new SDK and CLI versions also have breaking changes that don't depend on the API version, and they are licensed under Apache 2.0 instead of the MIT License. See SDK and CLI changes.

We've added the enforcement_status and enforcement_actions fields to user profiles, so you can see whether Anthropic has restricted or banned one of your end customers. To find the profiles that have an open restriction or ban, list your profiles with the new enforcement_status[] filter. See Check whether Anthropic has restricted or banned a profile.