LangChain v0.3 has been released for both Python and JavaScript ecosystems with notable changes and improvements. For Python, all packages have transitioned to Pydantic 2, and support for Python 3.8 will end following its life cycle in October 2024. JavaScript users are now required to explicitly install @langchain/core as a peer dependency, and callbacks have been made non-blocking by default. Deprecated entry points and self-query mechanisms have been removed, with alternatives provided in specific integration packages like @langchain/community and @langchain/google-vertexai. New features include a universal model constructor, utilities for managing chat models, and the ability to dispatch custom events. LangGraph, a tool for building stateful, multi-actor applications, is emphasized as the recommended method for creating agents. Improvements are planned for the multi-modal capabilities and integration documentation of LangChain in future releases. Comprehensive how-to guides are available for migrating to this new version, and feedback is encouraged via GitHub.