Upgrading and version history

The Anthropic Python SDK's version history tracks deprecations and removals of older Claude models, new integrations with AWS Bedrock and Microsoft platforms, and auth/credential handling improvements across releases. Versions also document fixes for streaming, token counting, agent toolsets, and MCP compatibility, alongside new features like Workload Identity Federation and self-hosted sandbox support. v1.1.0 adds Organization API endpoints, an updates thinking display mode, missing beta header values, and fixes for the pause_turn tool runner. v1.3.0 adds beta thinking-config types (BetaThinkingConfigAdaptiveParam, BetaThinkingConfigEnabledParam, BetaThinkingBlockBindingParam, BetaThinkingDroppedInputTransformation, BetaThinkingPrefixMismatchBehavior) and managed-agents model types (BetaManagedAgentsModel and param counterparts) to src/anthropic/types/beta/. v1.3.0 updates BetaUserProfile by adding external_user_onboarded_at and replacing the relationship field with access_type in user_profile_create_params.py and user_profile_update_params.py. v1.3.0 adds organization compliance settings as a compliance_settings sub-resource under beta.organization, exposing BetaComplianceSettings, BetaComplianceSettingsStateEnabled, and BetaComplianceSettingsStateDisabled types in src/anthropic/resources/beta/organization/compliance_settings.py.

Claude Sonnet 4 and Opus 4 were marked as deprecated in v0.95.0.[1] Claude Opus 4.1 was marked as deprecated in v0.106.0.[2] Claude Opus 4.1 models (claude-opus-4-1 and claude-opus-4-1-20250805) reached end-of-life on August 5, 2026 and were removed from the API and SDK in v0.121.0.[3] A new stop reason 'model_context_window_exceeded' was added to the API in v0.119.0.[4]

Support for Workload Identity Federation, interactive OAuth, and auth profiles was added to the client in v0.98.0.[5] In v0.117.0, credential material is kept out of traceback frame locals by wrapping secrets in SecretStr, preventing accidental credential leakage in error tracebacks.[6] In v1.0.0, the SDK's HTTP transport layer was rebuilt on httpx2 (replacing httpx 0.x), touching _base_client.py, _client.py, _streaming.py, _request.py, _response.py, _types.py, and over 130 additional files. The httpx2 upgrade in v1.0.0 introduces breaking changes to the public surface for constructing clients, passing custom transports, and handling responses; code that subclasses or monkey-patches the base client will likely require updates. A vendored httpx_aiohttp transport (src/anthropic/_vendor/httpx_aiohttp/) was added in v1.0.0 to support aiohttp-backed async HTTP usage.

The Microsoft Foundry SDK was added in v0.74.0 (November 2025).[7] A dedicated AWS client for Claude Platform on AWS was added in v0.101.0.[8] Support for self-hosted sandboxes in Claude Managed Agents (CMA) with sandbox helpers was added in v0.103.0.[9]

In v0.120.1, the MCP extra dependency was pinned to <2 due to a compatibility issue; v0.120.2 then added proper support for MCP SDK v2 alongside v1.[10]

Prior to v0.110.0, multiple calls to helper header merges would clobber the x-stainless-helper header instead of appending; the fix ensures existing tags are extended, never replaced.[11] The Bedrock client was not preserving stream event type; this was fixed in v0.110.0.[12] The async count_tokens method was missing the output_format/output_config merge block; this was fixed in v0.113.0.[13] The agent toolset read/edit tools previously raised UnicodeDecodeError on binary files; v0.119.0 fixed this by returning images and PDFs as base64 content blocks and erroring cleanly on other non-UTF-8 files.[14]

Python 3.8 support was dropped from the SDK.[15]

Sources

In v0.120.1, the MCP extra dependency was pinned to <2 due to a compatibility issue; v0.120.2 then added proper support for MCP SDK v2 alongside v1.[10]

Python 3.8 support was dropped from the SDK.[15]

Sources

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Upgrading and version history