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LangChain developer documentation update

langchain-changelog engineering-technology May 11, 2026 source →
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135
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engineering-technology
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6 min
Record
langchain-core==1.4.0

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LangChain Core improved JSON `get_format_instructions` using `Opik Agent Optimizer`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core improved LangSmith tracing by accepting integer temperature values in `_get_ls_params`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for built-in tools in Groq message content.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for VertexAI standard content.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added a warning for fallback GPT-2 tokenizer usage.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core improved error messages for missing titles in JSON schema functions.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for Python 3.14.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core version 1.4.0 was released.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added content-block-centric streaming (v2).

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core's streaming v2 (stream_v2/astream_v2) is marked as beta.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for passing lists of ToolOutputMixin instances to _format_output.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core deprecated `function_call` in favor of `tool_calls` for `get_buffer_string`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added PEP 702 __deprecated__ attribute support to the @deprecated decorator.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core automatically counts and stores metadata for tool call count.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core's BaseTool now supports extras.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added chat model and LLM invocation parameters to traceable metadata.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added LangSmith integration metadata to `create_agent` and `init_chat_model`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added `usage_metadata` to metadata in `LangChainTracer`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core started using `uuid7` for run IDs.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added ChatBaseten to its serializable mapping.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for imputing placeholder filenames for OpenAI file inputs.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for OpenAI tool search.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added a ChatAnthropicBedrock wrapper.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added the langchain-openrouter provider package.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for Google Maps grounding in the GenAI block translator.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core minted langchain-model-profiles and added a profile property to BaseChatModel.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core model profiles data is now distributed across packages.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core includes original block type in server tool results for Google GenAI.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added ContextOverflowError which is raised in Anthropic and OpenAI.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core model profiles added text_inputs and text_outputs.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for counting tokens from tool schemas approximately.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for scaling approximate token counts by reported usage.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added multimodal support to approximate token counting.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added 'approximate' alias in place of `count_tokens_approximately`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added an XML format option for `get_buffer_string`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for custom message separators in `get_buffer_string()`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added proxy support for Mermaid PNG rendering.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added support for drawing subgraphs using `pygraphviz`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added anti-SSRF hardening.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core hardened `load()` against untrusted manifests.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core restored cloud metadata IPs and link-local range in SSRF policy.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core added more sanitization to templates.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core hardened checks for txt files in deprecated prompt loading functions.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core deprecated `prompt.save` and `load_prompt` methods.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed `BaseMemory` (moved to `langchain-classic`).

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed items marked for removal in `schemas.py`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed `function_calling.py` utilities marked for removal.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed `pydantic_v1/`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed `get_relevant_documents`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed globals from `langchain-v1` and updated globals in `langchain-classic` and `langchain-core`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core removed deprecated items.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core improved performance by using reference counting for storing inherited run trees.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core improved performance by reducing streaming metadata.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core moved `BaseCrossEncoder` to `langchain-core`.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core improved error messages for non-JSON-serializable tool schemas.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core delegates to core implementation on invoke when streaming=True for OpenAI and Anthropic.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core restores add_user_message and add_ai_message methods.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core fixes PydanticOutputParser's get_format_instructions for v1 models.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core overrides streaming callback if the streaming attribute is set.

paraphrasestatedengineering-technologyMay 11, 2026

LangChain Core fixes string content when streaming with output_version="v1".

paraphrasestatedengineering-technologyMay 11, 2026