urllib3 Replace method

The Fix

pip install urllib3==1.25.11

Based on closed urllib3/urllib3 issue #1916 · 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

@@ -14,5 +14,4 @@ but can also be used independently.
 .. automodule:: urllib3.util
     :members:
-    :undoc-members:
     :show-inheritance:
diff --git a/src/urllib3/util/retry.py b/src/urllib3/util/retry.py

fix.md

Option A — Upgrade to fixed release\npip install urllib3==1.25.11\nWhen NOT to use: This fix is not applicable if the existing parameter names are required for backward compatibility.\n\n

Why This Fix Works in Production

Trigger: I'd already set my mind to doing this before this issue was raised. Unless another collaborator objects we'll be making this change.
Mechanism: The parameters 'method_whitelist' and 'DEFAULT_REDIRECT_HEADERS_BLACKLIST' in the Retry module had slavery connotations
Why the fix works: Renamed the parameters 'method_whitelist' and 'DEFAULT_REDIRECT_HEADERS_BLACKLIST' in the Retry module to neutral terms to avoid slavery connotations. (first fixed release: 1.25.11).

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

The parameters 'method_whitelist' and 'DEFAULT_REDIRECT_HEADERS_BLACKLIST' in the Retry module had slavery connotations
Production symptom (often without a traceback): I'd already set my mind to doing this before this issue was raised. Unless another collaborator objects we'll be making this change.

Proof / Evidence

GitHub issue: #1916
Fix PR: https://github.com/urllib3/urllib3/pull/2000
First fixed release: 1.25.11
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.95
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.78

Discussion

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

Jump to Sources Open on GitHub

“Yep, this is on my to-do list. Gotta jump through a few hoops to make it backwards compatible but also not appear in the documentation.”

@sethmlarson · 2020-08-03 · source

“I'd already set my mind to doing this before this issue was raised. Unless another collaborator objects we'll be making this change.”

@sethmlarson · 2020-08-05 · source

“Black is associated with evil in many cultures simply because black is the color of darkness, and in the dark you can not see anything,…”

@antoinesouchon1982 · 2020-08-05 · source

Failure Signature (Search String)

I'd already set my mind to doing this before this issue was raised. Unless another collaborator objects we'll be making this change.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
I'd already set my mind to doing this before this issue was raised. Unless another collaborator objects we'll be making this change.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
I'd already set my mind to doing this before this issue was raised. Unless another collaborator objects we'll be making this change.

What Broke

No production failures reported; change is for terminology improvement.

Why It Broke

The parameters 'method_whitelist' and 'DEFAULT_REDIRECT_HEADERS_BLACKLIST' in the Retry module had slavery connotations

Fix Options (Details)

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

pip install urllib3==1.25.11

When NOT to use: This fix is not applicable if the existing parameter names are required for backward compatibility.

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

Fix reference: https://github.com/urllib3/urllib3/pull/2000

First fixed release: 1.25.11

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

When NOT to Use This Fix

This fix is not applicable if the existing parameter names are required for backward compatibility.

Did This Fix Work in Your Case?

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

Prevention

Add a CI check that diffs key outputs after upgrades (OpenAPI schema snapshots, JSON payload shapes, CLI output).
Upgrade behind a canary and run integration tests against the canary before 100% rollout.

Version Compatibility Table

Version	Status
1.25.11	Fixed

Related Issues

No related fixes found.

Cluster: urllib3:configuration-error urllib3 hub urllib3 best practices All hubs All clusters

Related clusters: Data consistency SSL handshake Other

Sources

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

urllib3 Replace method_whitelist and DEFAULT_REDIRECT_HEADERS_BLACKLIST parameter names for the (Fix)