Celery Release version 4.2.0 (Fix)

The Fix

pip install celery==4.4.0rc5

Based on closed celery/celery issue #4387 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Open PR/Commit

@@ -570,13 +570,10 @@ def run(self, args=(), kwargs={}, group_id=None, chord=None,
                 if args and not self.immutable else self.args)
 
-        if self._frozen:
-            tasks, results = self._frozen
-        else:

fix.md

Option A — Upgrade to fixed release\npip install celery==4.4.0rc5\nWhen NOT to use: Do not use this fix if the task execution logic relies on frozen tasks for state management.\n\n

Why This Fix Works in Production

Trigger: I can help with the changelog.
Mechanism: Arguments were not propagated to chains inside groups, leading to unexpected behavior in task execution
Why the fix works: Propagates arguments to chains inside groups, addressing an issue where arguments were not correctly passed, which could lead to unexpected behavior in task execution. (first fixed release: 4.4.0rc5).

Production impact:

If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

Arguments were not propagated to chains inside groups, leading to unexpected behavior in task execution
Production symptom (often without a traceback): I can help with the changelog.

Proof / Evidence

GitHub issue: #4387
Fix PR: https://github.com/celery/celery/pull/4481
First fixed release: 4.4.0rc5
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.81

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“Would love to see this get released soon. I just spent time trying to figure out why automatic retries weren't working (#4341).”

@rsyring · 2018-01-27 · confirmation · source

“Milestone 4.2 is passed it's due date and several issues are still open (33/98 issues are still open (33%))”

@Skeen · 2018-01-08 · confirmation · source

“@georgepsarakis Any updates on 4.2? The time / timezone / eta bugfixes seem critical...”

@johnarnold · 2017-12-11 · source

“I am always in favor of releasing smaller bug fixe release as early as possible. I prefer django style release”

@auvipy · 2017-11-15 · source

Failure Signature (Search String)

I can help with the changelog.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
I can help with the changelog.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
I can help with the changelog.

What Broke

Tasks failed to execute correctly due to missing arguments, causing operational disruptions.

Why It Broke

Arguments were not propagated to chains inside groups, leading to unexpected behavior in task execution

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install celery==4.4.0rc5

When NOT to use: Do not use this fix if the task execution logic relies on frozen tasks for state management.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/celery/celery/pull/4481

First fixed release: 4.4.0rc5

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

Do not use this fix if the task execution logic relies on frozen tasks for state management.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
Pin production dependencies and upgrade only with a reproducible test that hits the failing path.

Version Compatibility Table

Version	Status
4.4.0rc5	Fixed

Related Issues

No related fixes found.

Cluster: celery:configuration-error Celery hub Celery best practices All hubs All clusters

Related clusters: Data consistency Duplicates Duplicate processing

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.