LangChain 0.3 dev releases

[ccurme]

Hello!

Please see below for an update on 0.3 dev releases.

As promised in #25244, we have released dev versions of a number of LangChain packages. Developers who are interested in an early preview of LangChain as migrated to Pydantic 2 should feel free to install and test these packages. Any feedback you are willing to share is helpful as we iron out the kinks and work toward a smooth 0.3.0 release.

Available packages:

• langchain-core==0.3.0.dev4
• langchain==0.3.0.dev1
• langchain-community==0.3.0.dev1
• langchain-text-splitters==0.3.0.dev1
• langchain-experimental==0.3.0.dev1
• langserve==0.3.0.dev1
• langchain-openai==0.2.0.dev2
• langchain-anthropic==0.2.0.dev1
• langchain-ollama==0.2.0.dev1
• langchain-huggingface==0.1.0.dev1
• langchain-aws==0.2.0.dev1
• langchain-fireworks==0.2.0.dev2
• langchain-groq==0.2.0.dev1
• langchain-mistralai==0.2.0.dev1
• langchain-weaviate==0.1.0.dev1
• langchain-mongodb==0.2.0.dev1
• langchain-qdrant==0.2.0.dev1
• langchain-pinecone==0.2.0.dev1
• langchain-elasticsearch==0.3.0.dev1
• langchain-google-community==2.0.0.dev2
• langchain-google-vertexai==2.0.0.dev1
• langchain-google-genai==2.0.0.dev1

You can also pip install with --pre to pick up the latest versions, e.g.,

pip install --upgrade --pre langchain-core langchain-openai

Known issues:

You may see PydanticDeprecatedSince20 warnings; we are actively working to resolve these.

Breaking changes:

Any sub-classing of LangChain models (e.g., BaseTool, BaseChatModel, etc.) should upgrade to use Pydantic 2-equivalent features-- for example, references to validator should be updated to field_validator. Refer to Pydantic's migration guide for details.

LangChain APIs that accept instances of Pydantic's BaseModel (e.g., BaseChatModel.bind_tools and BaseChatModel.with_structured_output) should receive Pydantic 2 objects.

Outside of these breaking changes, runtime errors are unexpected-- we'd appreciate bug reports on this Discussion.

[mraguth]

@ccurme Love to explore. Is there any changes to either PythonAstREPLTool or pandas dataframe agents in the 0.3 version?

[baskaryan]

No changes to either of those specifically. The main change in 0.3 is migrating to Pydantic 2.

[eyurtsev]

Adding some issues that were reported

#26250

[vermapratyush]

@ccurme Based on the feedback so far, do you have any insight into when we might expect the release candidate and stable versions of 0.3?

[baskaryan]

should have 0.3.0 out later today

[baskaryan]

v0.3 with Pydantic 2 support is out! #26544