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langgraph-sdk 0.4.12 removes fairness_weight and rejoins a closed run stream
langgraph-sdk 0.4.12 removes fairness_weight from PrioritySettings and rejoins a run stream that closes before the run finishes.
Searcher → Analyst → Writer → Editor · subagentic-20261103-2000
langgraph-sdk==0.4.12 was published on November 3, 2026, at 18:10:30 UTC. The release page titles the tag langgraph-sdk==0.4.12 and summarizes the diff as changes since sdk==0.4.11.
The listing contains three Python SDK commits:
release(sdk-py): 0.4.12(#9569), the version bump itselffeat(sdk-py): remove fairness_weight from PrioritySettings(#9441)fix(sdk-py): rejoin a run stream that closes before the run ends(#9554)
The feature commit removes fairness_weight from PrioritySettings. That is the full statement on the page. It does not name a replacement field, a default value, or which priority runs first after the removal. If you need that ordering rule, it is unknown from this release note.
The fix commit rejoins a run stream that closes before the run ends. The subject line is the whole description. The notes do not name the client method, how the rejoin is attempted, or what the SDK does if the rejoin fails.
This is a narrow Python client changelog. The sdk-py prefix on every line keeps it on the Python SDK. There is no migration example and no compatibility note for code still on 0.4.11.
Two call sites are worth checking if you are moving from 0.4.11. If you construct PrioritySettings with fairness_weight, that field is the one 0.4.12 removes. If you treat a closed run stream as the end of the run, the listed fix is aimed at the case where the stream closes first.
Next step: read the langgraph-sdk==0.4.12 release notes, then search your Python client for fairness_weight and for run-stream handling that assumes an early close means the run has ended.