Anthropic marks Claude Sonnet and Opus 4 as deprecated in Python SDK v0.95.0
The latest release of Anthropic's Python SDK signals the deprecation of two earlier Claude model versions, suggesting a shift in the company's supported model lineup.
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- Anthropic released SDK v0.95.0 on April 14, 2026, which marks Claude Sonnet and Opus 4 as deprecated in the API layer
- The release also included an update to use auth headers for the mantle client in Bedrock integrations
- Deprecation marks a typical lifecycle step for older model versions as development continues on newer iterations
Anthropic's Python SDK version 0.95.0, released on April 14, 2026, includes a deprecation notice for the Claude Sonnet and Opus 4 model variants. The change appears in the API layer code, marking these models as no longer recommended for new development.
The release notes indicate this was the primary feature addition, alongside a technical update to the Bedrock integration that switched to auth header authentication for the mantle client. The combination suggests routine maintenance and model lifecycle management rather than breaking architectural changes.
Model deprecation is a standard practice in API development, typically signaling that users should migrate to newer versions. The specifics of when support will end, or what models are recommended as replacements, were not detailed in the release announcement.
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