Celery The "retry_backoff" task argument is not working in

The Fix

pip install celery==4.4.0rc5

Based on closed celery/celery issue #4341 · 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%.

Jump to Verify Open PR/Commit

@@ -36,7 +36,7 @@
 from celery.utils.dispatch import Signal
 from celery.utils.functional import first, maybe_list, head_from_fun
-from celery.utils.time import timezone
+from celery.utils.time import timezone, get_exponential_backoff_interval
 from celery.utils.imports import gen_task_name, instantiate, symbol_by_name

repro.py

software -> celery:4.1.0 (latentcall) kombu:4.1.0 py:2.7.12
            billiard:3.5.0.2 py-amqp:2.1.4
platform -> system:Linux arch:64bit, ELF imp:CPython
loader   -> celery.loaders.app.AppLoader
settings -> transport:amqp results:cache+memcached://memcached:11211/

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\npip install celery==4.4.0rc5\nWhen NOT to use: Do not use this fix if you require the original behavior of fixed retry intervals.\n\n

Why This Fix Works in Production

Trigger: The "retry_backoff" task argument is not working in 4.1.0 version
Mechanism: Adds options for exponential backoff with task autoretry, addressing the issue where the 'retry_backoff' argument was not functioning as expected in version 4.1.0.
Why the fix works: Adds options for exponential backoff with task autoretry, addressing the issue where the 'retry_backoff' argument was not functioning as expected in version 4.1.0. (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

Triggered by an upgrade/regression window: 31.069687–31.346456 breaks; 4.4.0rc5 is the first fixed release.
Production symptom (often without a traceback): from requests.exceptions import RequestException

Proof / Evidence

GitHub issue: #4341
Fix PR: https://github.com/celery/celery/pull/4101
First fixed release: 4.4.0rc5
Affected versions: 31.069687–31.346456
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.61

Discussion

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

Jump to Sources Open on GitHub

“@auvipy the PR with this feature was merged after 4.1.0 was released.”

@georgepsarakis · 2017-12-18 · confirmation · source

“I thought I was doing something wrong :(”

@WoLfulus · 2018-02-08 · source

“I'm also confused by this”

@Fingel · 2017-11-16 · source

“Can you update the docs or release a new version? This is confusing and gives new users the idea they can't trust Celery docs...”

@divad · 2018-01-22 · source

Failure Signature (Search String)

The "retry_backoff" task argument is not working in 4.1.0 version

Copy-friendly signature

signature.txt

Failure Signature
-----------------
from requests.exceptions import RequestException
@app.task(autoretry_for=(RequestException,), retry_backoff=True)

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
from requests.exceptions import RequestException
@app.task(autoretry_for=(RequestException,), retry_backoff=True)

Minimal Reproduction

repro.py

software -> celery:4.1.0 (latentcall) kombu:4.1.0 py:2.7.12
            billiard:3.5.0.2 py-amqp:2.1.4
platform -> system:Linux arch:64bit, ELF imp:CPython
loader   -> celery.loaders.app.AppLoader
settings -> transport:amqp results:cache+memcached://memcached:11211/

What Broke

Tasks were retrying every 180 seconds instead of the expected exponential backoff.

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 you require the original behavior of fixed retry intervals.

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/4101

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 you require the original behavior of fixed retry intervals.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

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
31.069687	Broken
31.346456	Broken
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.

Celery The "retry_backoff" task argument is not working in 4.1.0 version (Fix)