langchain-ai/langgraph · error · NotImplementedError

RemoteGraph.astream_events(version={version!r}) is not imple

Error message

RemoteGraph.astream_events(version={version!r}) is not implemented; use astream() for v1/v2 streaming or version='v3'.

What it means

Error "RemoteGraph.astream_events(version={version!r}) is not implemented; use astream() for v1/v2 streaming or version='v3'." thrown in langchain-ai/langgraph.

Source

Thrown at libs/langgraph/langgraph/pregel/remote.py:1101

        config: RunnableConfig | None = None,
        *,
        version: Literal["v1", "v2", "v3"] = "v2",
        interrupt_before: All | Sequence[str] | None = None,
        interrupt_after: All | Sequence[str] | None = None,
        control: Any = None,
        transformers: Sequence[Any] | None = None,
        headers: dict[str, str] | None = None,
        **kwargs: Any,
    ) -> Any:
        """Async-stream events from this remote graph.

        For `version="v3"`, awaits to an `_AsyncRemoteGraphRunStream`, matching
        the local `Pregel.astream_events(version="v3")` awaitable contract:
        `async with await rg.astream_events(..., version="v3") as run`. For
        `version="v1"`/`"v2"`, raises NotImplementedError (use `astream`).
        """
        if version != "v3":
            raise NotImplementedError(
                f"RemoteGraph.astream_events(version={version!r}) is not "
                "implemented; use astream() for v1/v2 streaming or "
                "version='v3'."
            )
        self._reject_v3_unsupported(
            control=control,
            transformers=transformers,
            interrupt_before=interrupt_before,
            interrupt_after=interrupt_after,
            extra_kwargs=kwargs,
        )
        client = self._validate_client()
        sanitized = self._sanitize_config(merge_configs(self.config, config))
        thread_id = sanitized.get("configurable", {}).pop("thread_id", None)
        merged_headers = (
            _merge_tracing_headers(headers) if self.distributed_tracing else headers
        )
        sdk_thread = client.threads.stream(

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/langgraph/langgraph/pregel/remote.py:1101 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of langchain-ai/langgraph@38031739e5 (2026-08-26). Data as JSON: /api/errors/4a088a08e124b862. Report an issue: GitHub.