LangGraph

langgraph v1.2.0 This release adds finer-grained control over node execution (timeouts, error recovery, and graceful shutdown), a new channel type that cuts checkpoint overhead for long-running threads, and a new content-block-centric streaming API (v3) with typed, per-channel projections. DeltaChannel (beta): A new channel type that stores only the incremental delta at each step rather than re-serializing the full accumulated value. Most useful for channels that grow large over time, for example a message list in a long-running thread. Use snapshot_frequency=K to write a full snapshot every K steps and bound read latency. Per-node timeouts: Pass timeout= to add_node to cap how long a single attempt may run. Set a hard wall-clock limit (run_timeout), an idle limit that resets on progress (idle_timeout), or both via TimeoutPolicy. When the limit fires, LangGraph raises NodeTimeoutError, clears writes from that attempt, and hands off to the retry policy. Async nodes only. Node-level error handlers: Pass error_handler= to add_node to run a recovery function after all retries are exhausted. The handler receives a typed NodeError and can return a Command to update state and route to a different node, useful for Saga/compensation patterns. Graceful shutdown: Stop an in-flight run cooperatively after the current superstep completes, and save a resumable checkpoint. Create a RunControl and call request_drain() from any thread; the run raises GraphDrained and can be resumed later with the same config. New event streaming API (beta): Pass version="v3" to stream_events() / astream_events() for a content-block-centric protocol with typed, per-channel projections (run.values, run.messages, run.lifecycle, run.subgraphs) plus opt-in transformers for updates, custom events, checkpoints, tasks, and debug. run.messages yields one ChatModelStream per LLM call with typed sub-projections for text, reasoning, tool calls, and usage. version="v1" and version="v2" are unchanged. Timeouts and error handlers are Python-only; retry policies continue to work in both Python and TypeScript.

langgraph v1.1.0 Type-safe streaming (version="v2"): Pass version="v2" to stream() / astream() for unified StreamPart output with type, ns, and data keys on every chunk. Each mode has its own TypedDict, all importable from langgraph.types. See streaming docs. Type-safe invoke (version="v2"): Pass version="v2" to invoke() / ainvoke() to get a GraphOutput object with .value and .interrupts attributes. See invoke docs. Pydantic and dataclass coercion: With version="v2", invoke() and values-mode stream output are automatically coerced to your declared Pydantic model or dataclass type. Fixed time travel with interrupts and subgraphs: Replays no longer reuse stale RESUME values, and subgraphs correctly restore the checkpoint for the parent's historical state. Fully backwards compatible: version="v2" is opt-in. GraphOutput supports deprecated dict-style access for gradual migration.

v1.0.0 langchain Release notes Migration guide langgraph Release notes Migration guide

v1.0.0 langchain Release notes Migration guide langgraph Release notes Migration guide

v1.1.0 @langchain/langgraph Introducing StateSchema - a cleaner, library-agnostic way to define graph state that works with any Standard Schema-compliant validation library. Standard JSON Schema support LangGraph now supports Standard JSON Schema, an open specification implemented by Zod 4, Valibot, ArkType, and other schema libraries. This means you can use your preferred validation library without lock-in: New state value primitives ReducedValue: Define fields with custom reducers for accumulating values. Supports separate input and output schemas for type-safe reducer inputs. UntrackedValue: Define transient state that exists during execution but is never checkpointed - useful for database connections, caches, or runtime-only configuration. MessagesValue: A prebuilt ReducedValue for chat messages with the standard messages reducer. Type helper exports New exported type utilities for typing functions outside the graph builder: GraphNode - Type node functions with full inference ConditionalEdgeRouter - Type conditional edge routers The existing Annotation and zod-based API continues to work unchanged - StateSchema is an additional option for those who prefer schema-first definitions.