langchain-core

The upgrade can be completed via the command pip install -U langchain-core==1.6.6.

Patch-level updates generally do not introduce breaking changes and can typically be applied directly without modifying existing code.

langchain-core 1.6.6 is a patch-level update that introduces no breaking changes.

The LangChain team released a langchain-core version 1.6.6 update.

langchain-core 1.6.9 is a minor version iteration following 1.6.8.

langchain-core is the foundational dependency of the entire LangChain framework, carrying key capabilities such as the Runnable interface, message abstraction, and the callback system.

LangChain's Claude integration is implemented through the langchain-anthropic sub-package, but the foundational abstractions for model compatibility are defined in langchain-core.

The langchain-core 1.6.12 Release was published by the github-actions bot, and the commit has passed GPG signature verification.

Projects that pin exact versions using requirements.txt or poetry.lock need to update proactively to get the fix; constraints that allow the patch number to float, such as ~=1.6.0 or ^1.6.0, will automatically pick up such small fixes.

Before 1.6.12, when the content-block-start event was triggered, the extras information attached to the content block was not correctly passed into the event object.

The fix in 1.6.12 ensures that extras are correctly propagated when the event is constructed.

For production environments, if the current version runs stably and you have not encountered the extras propagation issue, there is no need to rush the upgrade; if you are using streaming content block related functionality, especially scenarios that need to read extras, 1.6.12 is worth including in your upgrade plan.

The changelog for langchain-core 1.6.12 contains only two entries: the version number release commit (#41277) and the fix for the extras propagation issue on content block start events (#41272).

The LangChain core library has recently adopted a fast, small-step release cadence, with each version focusing on a few fixes.

langchain-core uses the semantic version form major.minor.patch, and 1.6.12 is a patch number increment, which by convention indicates backward-compatible bug fixes.

In 1.6.11, LangChainTracer supports accepting an address parameter at initialization, corresponding to PR #41006.

The LangChain ecosystem consists of multiple independently released packages: langchain-core is the lowest-level abstraction layer, defining basic protocols such as Runnable, message types, tool interfaces and tracing; langchain provides high-level wrappers for chains and Agents; langgraph focuses on graph-based state machine workflows. The three have independent version numbers and are not forced to align.

If a newly added API in the underlying langchain-core is not explicitly exposed, the upper-layer langchain or langgraph may not be able to use it directly, and its pass-through depends on the maintenance pace of each upper-layer package.

If the current tracing configuration relies entirely on default environment variables and runs stably, the urgency of upgrading to 1.6.11 is not high.

Since 1.6.10, langchain-core 1.6.11 contains two commits: the release commit release(core): 1.6.11 (#41260) and the feature enhancement feat(core): accept address inside LangChainTracer (#41006).