[Release] langchain-ai/langchain langchain-openai==1.2.1: langchain-openai==1.2.1

langchain-openai version 1.2.1 is a hotfix release that bumps minimum core versions and adds support for GPT-5.5 Pro in the Responses API. The release includes content-block-centric streaming improvements (v2) and refreshed model profile data. Key changes focus on API compatibility, new model support, and streaming enhancements.

Key Points

• •Bumped minimum core versions to ensure compatibility with latest langchain-core dependencies
• •Added GPT-5.5 Pro model support to the Responses API check for proper model validation
• •Implemented content-block-centric streaming (v2) for improved streaming architecture in core
• •Refreshed model profile data to reflect current model capabilities and configurations
• •Hotfix release addressing critical compatibility and feature gaps from 1.2.0
• •Maintains backward compatibility while extending OpenAI model support

Workflow Diagram

Concepts