LangChain

Changes since langchain==1.4.8

• release(langchain): 1.4.9 (#41684)
• feat(core): standardize model refusal content blocks (#41582)

• > [!WARNING] > Python 3.10 support will be dropped in `langchain-core` 1.8.0 and `langchain` 1.5.0. The current minor versions are the last to support Python 3.10. Please upgrade to Python 3.11 or later. Changes since langchain==1.4.7 chore(langchain): bump langchain-core (#41640)
• release(langchain): 1.4.8 (#41636)
• revert: patch vulnerable integration dependencies (#41481)
• chore(infra): relax third-party dependency upper bounds (#41407)

Changes since langchain==1.4.6

• chore(langchain): update lockfile (#41402)
• release(langchain): 1.4.7 (#41401)
• feat(core,langchain,standard-tests): read tool-call-delta in stream consumers (#41246)
• feat(core): accept address inside LangChainTracer (#41006)

Changes since langchain==1.4.5 release(langchain): 1.4.6 (#41247) feat(langchain): add opt-in per-call interrupts to HITL middleware (#41062)

Changes since langchain==1.4.4 release(langchain): 1.4.5 (#41226) feat(langchain): accept summarizer in SummarizationMiddleware (#41225)

Changes since langchain==1.4.3

• release(langchain): 1.4.4 (#41163)
• fix(langchain): (SummarizationMiddleware) retry summary step on context overflow (#41159)
• chore(langchain): bump minimum FastMCP to 4.0.11 (#41054)

Changes since langchain==1.4.2

• release(langchain): 1.4.3 (#40888)
• fix(langchain): sanitize cache settings for fallback models (#40886)
• feat(langchain): support Bedrock Mantle chat models in init_chat_model (#40837)
• fix(langchain): recognize GPT-6 structured output without profiles (#40844)
• docs(infra): fix AGENTS.md root setup guidance and package doc accuracy (#40794)
• fix(langchain): repair invalid tool calls in create_agent (#40530)
• chore(langchain): remove commented-out cohere extra (#40713)

Changes since langchain==1.4.1 release(langchain): 1.4.2 (#40621) fix(langchain): preserve model-generated tool calls in HITL tool call edits and add notice to ToolMessage (#40463)

Changes since langchain==1.4.0

• release(langchain): 1.4.1 (#40498)
• fix(langchain): preserve open MCP object arguments (#40414)
• fix(langchain): correct InterruptOnConfig documentation (#40140)

Changes since langchain==1.3.18

• docs(langchain): runnable langchain.mcp examples (#39976)
• feat(langchain): langchain.mcp namespace, MCPAdapter (#39939)
• perf(anthropic,langchain): omit middleware trace inputs (#40098)
• fix(langchain): include model destination in agent tool routing (#38355)
• chore(langchain): bump vcrpy test dependency minimum to >=8.2.0 (#39942)

Changes since langchain==1.3.17

• release(langchain): 1.3.18 (#39966)
• fix(langchain): preserve content-block shape in PIIMiddleware redaction (#39894)
• fix(core): shore up indexing in genai v1 streaming content (#39964)

Changes since langchain==1.3.16

• release(langchain): 1.3.17 (#39893)
• fix(langchain): frame custom HITL rejection reasons (#39773)

Changes since langchain==1.3.15

• release(langchain): 1.3.16 (#39806)
• feat(core): add standard model exception types (#39538)
• feat(langchain): support custom token_counter in ContextEditingMiddleware (#39754)
• fix(langchain): re-raise non-retryable exceptions in ModelRetryMiddleware (#38960)
• chore(langchain): update docs on error handling for json schema (#39632)
• fix(langchain): preserve final repeated schema ordering (#39284)

Changes since langchain==1.3.14

• release(langchain): 1.3.15 (#39595)
• feat(langchain): expose trace_policy on AgentMiddleware (#38910)
• chore(langchain): fix type errors in tests (#39589)
• fix(langchain): preserve history on SummarizationMiddleware summary failure (#39268)
• fix(langchain): handle import error in LLMToolEmulator by model (#39290)
• refactor(langchain): update doc strings (#39305)
• feat(langchain): add state_schema param to wrap_tool_call (#39292)
• fix(langchain): re-export PIIMatch from middleware package (#39291)

Changes since langchain==1.3.13

• release(langchain): 1.3.14 (#38883)
• fix(langchain): only retry retryable exceptions in ToolRetryMiddleware (#38845)
• feat(langchain): ToolErrorMiddleware (#38781)

Changes since langchain==1.3.12

• release(langchain): 1.3.13 (#38787)
• feat(langchain): add meta extra and support langchain-meta in init_chat_model (#38786)
• feat(openai): support explicit prompt caching (#38762)

Changes since langchain==1.3.11

• release(langchain): 1.3.12 (#38730)
• fix(langchain): propagate interrupts through ToolRetryMiddleware (#38722)
• fix(langchain): avoid shared process-group kill in shell middleware (#36359)
• fix(langchain): sanitize anthropic cache markers on fallback retries (#37867)
• style: fix some ruff preview rules in langchain_v1 and standard-tests (#38657)
• chore(langchain): add types in agent middleware tests (#38188)

Changes since langchain==1.3.10

• release(langchain): 1.3.11 (#38377)
• fix(langchain,openai): only set strict=True on tools for OpenAI-compatible models in ProviderStrategy (#38370)
• docs(langchain): document summarization prompt contract (#38256)

Changes since langchain==1.3.9

• release(langchain): 1.3.10 (#38255)
• fix(langchain): switch summary format (#38171)
• fix(langchain): detect provider strategy for dated gpt-5.2/gpt-5.4 snapshots (#38222)
• chore(langchain): improve typing in tests (#38163)
• release(openai): 1.3.2 (#38130)
• hotfix(openai): switch version (#38123)
• release(openai): 1.4.0 (#38120)
• docs: refresh README installation and resources (#38119)
• test(core,langchain): update tests for explicit deserialization allowlists (#38118)
• release(core): 1.4.7 (#38111)
• release(anthropic): 1.4.6 (#38105)

Changes since langchain==1.3.8

• release(anthropic): 1.4.6 (#38105)
• release(langchain): 1.3.9 (#38104)
• fix(langchain,anthropic): confine file-search results and tighten anthropic allowed_prefixes (#38106)

Changes since langchain==1.3.7

• release(langchain): 1.3.8 (#38096)
• style(core,langchain,langchain-classic,partners): replace double backticks in docstrings (#38095)
• release(core): 1.4.6 (#38061)
• chore(langchain): add overloads to create_agent (#34309)
• chore(infra): bump mypy to 2.1 and unify type-check config across the monorepo (#36470)
• fix(langchain): support async middleware decorator typing (#34584)
• fix(langchain): tighten structured output model fallbacks (#38042)
• release(anthropic): 1.4.5 (#38036)
• hotfix(core): bump lockfile(s) (#38032)
• refactor(langchain): refactor test_create_agent_tool_validation (#34443)

Changes since langchain==1.3.6

• release(langchain): 1.3.7 (#38024)
• style(langchain): add ruff rules ARG (#34435)
• feat(langchain): add ProviderToolSearchMiddleware (#37969)
• chore(langchain): activate mypy warn_return_any (#34249)
• test(langchain): mark legacy trigger view for 2.0 removal (#38002)

Changes since langchain==1.3.5 release(langchain): 1.3.6 (#38001) fix(langchain): preserve summarization trigger compatibility (#38000)

Changes since langchain==1.3.4

• release(langchain): 1.3.5 (#37998)
• feat(langchain): port AND-capable trigger conditions to SummarizationMiddleware (#34576)
• hotfix(openai): min core dep (#37990)
• feat(openai): support apply_patch built-in tool (#37157)
• chore: bump dependencies (#37892)

Changes since langchain==1.3.3 release(langchain): 1.3.4 (#37861) fix(langchain): improve HITL rejection guidance (#37859)

Changes since langchain==1.3.2

• release(langchain): 1.3.3 (#37843)
• chore(langchain): bump langgraph to 1.2.4 (#37857)
• chore(langchain): loosen langgraph dep range (#37855)
• feat(langchain): project subagent runs onto typed run.subagents channel (#37739)
• feat(langchain): add interrupt_mode and when predicate to HumanInTheLoopMiddleware (#37579)

Changes since langchain==1.3.1

• fix(langchain): land final answer in last AIMessage for TodoListMiddleware (#37643)
• feat(langchain): redact streamed PII in flight on PIIMiddleware (#37616)
• chore(infra): bump langchain-tests floor to 1.1.9 (#37610)
• release(standard-tests): 1.1.9 (#37609)
• feat(langchain): register stream transformers on middleware (#37591)
• refactor(langchain): clean redundancy ifelse. (#37448)
• hotfix: bump lockfiles (#37508)
• chore(core,langchain,openai): refresh stale OpenAI model references (#37487)
• fix(langchain): sort glob_search results by mtime (newest first) (#37462)

Changes since langchain==1.3.0 release(langchain): 1.3.1 (#37454) fix(langchain): alias Bedrock providers in summarization token check (#37453)

This release adds support for version="v3" in stream_events / astream_events for langchain agents. Refer to the event streaming guide for details.

Changes since langchain==1.2.17

• release(langchain): 1.2.18 (#37250)
• revert: feat(langchain): ls_agent_type tag on create_agent calls (#37249)
• chore(langchain-classic): deprecate hub, limit loads/dumps (#37234)
• refactor(langchain-classic): retarget deprecations to create_agent, other chores (#37164)
• chore(langchain,langchain-classic): uncomment optional deps (#37163)
• release(fireworks): 1.2.1 (#37113)