What's New in LangChain v0.3

1. LangChain v0.3 release for Python and JavaScript ecosystems.
2. Python changes include upgrade to Pydantic 2, end-of-life for Pydantic 1, and end-of-life for Python 3.8.
3. JavaScript changes entail the addition of @langchain/core as a peer dependency, explicit installation requirement, and non-blocking callbacks by default.
4. Removal of deprecated document loader and self-query entrypoints from “langchain” in favor of entrypoints in @langchain/community and integration packages.
5. Deprecated usage of objects with a “type” as a BaseMessageLike in favor of MessageWithRole.
6. Improvements include moving integrations to individual packages, revamped integration docs and API references, simplified tool definition and usage, added utilities for interacting with chat models, and dispatching custom events.
7. How-to guides available for migrating to the new version for Python and JavaScript.
8. Versioned documentation available with previous versions still accessible online.
9. LangGraph integration recommended for building stateful, multi-actor applications with LLMs in LangChain v0.3.
10. Upcoming improvements in LangChain’s multi-modal capabilities and ongoing work on enhancing documentation and integration reliability.