fix(langgraph): require `langgraph-api>=0.10.0` for `DeltaChannel` by sydney-runkle · Pull Request #8043 · langchain-ai/langgraph

Sydney Runkle (sydney-runkle) · 2026-06-10T20:56:08Z

A graph that uses DeltaChannel depends on server-side reconstruction support added in langgraph-api>=0.10.0. When such a graph is run under an older API server, delta channels fail at runtime. StateGraph.compile now reads importlib.metadata.version("langgraph-api") and raises a RuntimeError with an upgrade hint when it is <0.10.0; packaging.version.Version keeps release candidates such as 0.10.0rc1 below the final 0.10.0 boundary. The check is a no-op when langgraph-api is not installed (local execution) or when the graph has no delta channel.

Verified end-to-end against real langgraph-api releases: 0.9.0 raises at compile time, 0.10.0 compiles successfully.

Self-Hosted Release Note

StateGraph.compile now raises a clear error when a graph uses DeltaChannel but the installed langgraph-api is <0.10.0, prompting an upgrade instead of failing later at runtime.

Test Plan

Compiling a DeltaChannel graph raises under langgraph-api<0.10.0 (including 0.10.0rc1), succeeds at >=0.10.0, and is silent when langgraph-api is absent or the graph has no delta channel.

Made by Open SWE

A graph using `DeltaChannel` reconstructs state via the saver's `get_delta_channel_history` API (added in `langgraph-checkpoint>=4.1.0`). Savers from older packages lack it and fail at runtime. `StateGraph.compile` now warns at compile time so users know to upgrade `langgraph-checkpoint`. Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

Shivani . (Shivani767) · 2026-06-11T08:37:12Z

I have a fix ready for this in PR #8044. Could you please assign this issue to me?

Replace the checkpointer-capability heuristic with a direct `langgraph-api` version check: `DeltaChannel` reconstruction needs server-side support added in `langgraph-api>0.9.0`. `StateGraph.compile` now raises a `RuntimeError` when a delta-channel graph is compiled under an older API server, and is a no-op when `langgraph-api` is not installed (local execution). Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

Quanzheng Long (longquanzheng) · 2026-06-12T17:24:13Z

+        return
+    if Version(api_version) > _MIN_DELTA_CHANNEL_API_VERSION:
+        return
+    raise RuntimeError(


I thought we can just fallback to non-delta channel, but raising error may be even better since they explictly want to get the benefits of delta channel.

i think we want to raise bc delta channels have different types of reducers

Quanzheng Long (longquanzheng) · 2026-06-12T17:26:39Z

+        api_version = metadata.version("langgraph-api")
+    except metadata.PackageNotFoundError:
+        return
+    if Version(api_version) > _MIN_DELTA_CHANNEL_API_VERSION:


Would it include the 0.10.0rcs?
like 0.10.0rc3?

maybe even better to just check on >=0.10.0.
because all the RCs in 0.1.0 don't have prune support.

Use a `>=` bound (raise below 0.9.0) and simplify the check: drop the module-level constant and the early-return ladder. Verified end-to-end against real langgraph-api releases — 0.8.6 raises, 0.10.0 compiles. Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

Sydney Runkle (sydney-runkle) · 2026-06-17T16:42:01Z

Open SWE (@open-swe) can you please do this

oh interesting. I was thinking of try import the version constant in langgraph-api, but I guess either way would work.also also let's just check on >=0.10.0, we don't want to include RCs for this particular condition

Raise for API versions below 0.10.0 so prereleases such as 0.10.0rc1 are not accepted by the delta-channel compatibility check. Verified against real langgraph-api releases: 0.9.0 raises and 0.10.0 compiles. Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

Use the version constant exported by `langgraph-api` instead of package metadata for the DeltaChannel API compatibility check. This keeps the check aligned with the API package itself while still avoiding a hard dependency when `langgraph-api` is absent. Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

Revert the optional `langgraph_api.__version__` import path in favor of the cleaner `importlib.metadata.version("langgraph-api")` check for DeltaChannel API compatibility. This avoids importing the optional API package at compile time while preserving the same version boundary. Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

open-swe

Open SWE Review found 1 potential issue.

Open in Web • View Open SWE trace

open-swe · 2026-06-17T21:07:13Z

            CompiledStateGraph: The compiled `StateGraph`.
        """
        checkpointer = ensure_valid_checkpointer(checkpointer)
+        _check_delta_channel_api_support(self.channels)


🟠 Frozen test env rejects DeltaChannel graphs

This compile-time check runs in the langgraph test environment, but CI installs dependencies with uv sync --frozen --group test --no-dev; on the 3.11-3.13 matrix the frozen libs/langgraph/uv.lock pulls langgraph-api==0.6.39 via langgraph-cli[inmem]. As a result, every existing test that compiles a DeltaChannel graph now fails before running. I reproduced the CI environment with Python 3.13 and g.compile() raises RuntimeError: DeltaChannel requires langgraph-api>=0.10.0, but 0.6.39 is installed. Please update the test/CI lock or dependency constraint to install langgraph-api>=0.10.0 alongside this check.

(Refers to line 1242)

Your feedback helps Open SWE learn. React with 👍 or 👎 to tell us if this review comment was useful.

Quanzheng Long (longquanzheng)

if you can, or someone else (including me), create a deployment to use this code with pinned lg-api to 0.9.0 to see if it fail.

Quanzheng Long (longquanzheng) · 2026-06-17T21:45:42Z

+        api_version = metadata.version("langgraph-api")
+    except metadata.PackageNotFoundError:
+        return
+    if Version(api_version) < Version("0.10.0"):


we are going to release 0.10.1 to fix the read+prune bug found by Parker.

maybe we can hold on with that(but not sure 0.10.1 will come tomorrow), or we can release this one, and then update this value to 0.10.1 in next release.

wdyt?

yeah we can hold off on this one

Christian Bromann (christian-bromann) · 2026-06-17T22:43:11Z

How do we guarantee this for JS deployments?

github-actions Bot added the internal label Jun 10, 2026

Shivani . (Shivani767) mentioned this pull request Jun 11, 2026

fix: persist DeltaChannel writes on empty thread #8044

Closed

open-swe Bot changed the title ~~feat(langgraph): warn when checkpointer lacks DeltaChannel support~~ fix(langgraph): check langgraph-api version for DeltaChannel support Jun 11, 2026

Quanzheng Long (longquanzheng) reviewed Jun 12, 2026

View reviewed changes

open-swe Bot changed the title ~~fix(langgraph): check langgraph-api version for DeltaChannel support~~ fix(langgraph): require langgraph-api>=0.9.0 for DeltaChannel Jun 15, 2026

open-swe Bot changed the title ~~fix(langgraph): require langgraph-api>=0.9.0 for DeltaChannel~~ fix(langgraph): require langgraph-api>=0.10.0 for DeltaChannel Jun 17, 2026

Sydney Runkle (sydney-runkle) and others added 2 commits June 17, 2026 17:01

Sydney Runkle (sydney-runkle) marked this pull request as ready for review June 17, 2026 20:58

open-swe Bot reviewed Jun 17, 2026

View reviewed changes

Quanzheng Long (longquanzheng) approved these changes Jun 17, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

fix(langgraph): require `langgraph-api>=0.10.0` for `DeltaChannel`#8043

fix(langgraph): require `langgraph-api>=0.10.0` for `DeltaChannel`#8043
Sydney Runkle (sydney-runkle) wants to merge 6 commits into
mainfrom
sydney-runkle/langgraph/delta-channel-checkpointer-warning

Sydney Runkle (sydney-runkle) commented Jun 10, 2026 •

edited by open-swe Bot

Loading

Uh oh!

Shivani . (Shivani767) commented Jun 11, 2026

Uh oh!

Uh oh!

Quanzheng Long (longquanzheng) Jun 12, 2026

Uh oh!

Sydney Runkle (sydney-runkle) Jun 18, 2026

Uh oh!

Quanzheng Long (longquanzheng) Jun 12, 2026

Uh oh!

Sydney Runkle (sydney-runkle) commented Jun 17, 2026

Uh oh!

open-swe Bot left a comment

Uh oh!

open-swe Bot Jun 17, 2026

Uh oh!

Quanzheng Long (longquanzheng) left a comment

Uh oh!

Quanzheng Long (longquanzheng) Jun 17, 2026

Uh oh!

Sydney Runkle (sydney-runkle) Jun 18, 2026

Uh oh!

Christian Bromann (christian-bromann) commented Jun 17, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Uh oh!

Conversation

Sydney Runkle (sydney-runkle) commented Jun 10, 2026 • edited by open-swe Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Self-Hosted Release Note

Test Plan

Uh oh!

Shivani . (Shivani767) commented Jun 11, 2026

Uh oh!

Uh oh!

Quanzheng Long (longquanzheng) Jun 12, 2026

Choose a reason for hiding this comment

Uh oh!

Sydney Runkle (sydney-runkle) Jun 18, 2026

Choose a reason for hiding this comment

Uh oh!

Quanzheng Long (longquanzheng) Jun 12, 2026

Choose a reason for hiding this comment

Uh oh!

Sydney Runkle (sydney-runkle) commented Jun 17, 2026

Uh oh!

open-swe Bot left a comment

Choose a reason for hiding this comment

Uh oh!

open-swe Bot Jun 17, 2026

Choose a reason for hiding this comment

Uh oh!

Quanzheng Long (longquanzheng) left a comment

Choose a reason for hiding this comment

Uh oh!

Quanzheng Long (longquanzheng) Jun 17, 2026

Choose a reason for hiding this comment

Uh oh!

Sydney Runkle (sydney-runkle) Jun 18, 2026

Choose a reason for hiding this comment

Uh oh!

Christian Bromann (christian-bromann) commented Jun 17, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Sydney Runkle (sydney-runkle) commented Jun 10, 2026 •

edited by open-swe Bot

Loading