urllib3 No released version supporting Python 3.10 (Fix)

The Fix

pip install urllib3==1.26.6

Based on closed urllib3/urllib3 issue #2238 · PR/commit linked

Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.

Open PR/Commit

@@ -44,7 +44,7 @@ jobs:
             experimental: false
             nox-session: test_brotlipy
-          - python-version: 3.10.0-alpha.7
+          - python-version: 3.10.0-beta.2
             os: ubuntu-latest

fix.md

Option A — Upgrade to fixed release\npip install urllib3==1.26.6\nWhen NOT to use: This fix should not be applied if compatibility with earlier Python versions is required.\n\n

Why This Fix Works in Production

Trigger: I'm trying to start porting my code to Python 3.10. One of the issues is that some `pkg_resources` stuff has changed and there's been an update of six.
Mechanism: Fixes warnings in Python 3.10 and will need to be backported to the 1.26.x branch, which will support Python 3.10 with an updated version of six.
Why the fix works: Fixes warnings in Python 3.10 and will need to be backported to the 1.26.x branch, which will support Python 3.10 with an updated version of six. (first fixed release: 1.26.6).

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

Shows up under Python 3.10 in real deployments (not just unit tests).
Production symptom (often without a traceback): I'm trying to start porting my code to Python 3.10. One of the issues is that some `pkg_resources` stuff has changed and there's been an update of six.

Proof / Evidence

GitHub issue: #2238
Fix PR: https://github.com/urllib3/urllib3/pull/2209
First fixed release: 1.26.6
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.95
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.76

Discussion

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

Jump to Sources Open on GitHub

“Six related issue was fixed in https://github.com/benjaminp/six/pull/352”

@tirkarthi · 2021-05-21 · confirmation · source

“Here's the issue that I see: https://github.com/flyingcircusio/batou/runs/2638868539?check_suite_focus=true#step:6:245”

@ctheune · 2021-05-21 · source

“We're not planning on releasing main soon, there's still a good amount of work to do for v2.0. Python 3.10 support will be coming to…”

@sethmlarson · 2021-05-21 · source

“Great, thanks! Do you need help with that?”

@ctheune · 2021-05-21 · source

Failure Signature (Search String)

I'm trying to start porting my code to Python 3.10. One of the issues is that some `pkg_resources` stuff has changed and there's been an update of six.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
I'm trying to start porting my code to Python 3.10. One of the issues is that some `pkg_resources` stuff has changed and there's been an update of six.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
I'm trying to start porting my code to Python 3.10. One of the issues is that some `pkg_resources` stuff has changed and there's been an update of six.

Environment

Python: 3.10

Fix Options (Details)

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

pip install urllib3==1.26.6

When NOT to use: This fix should not be applied if compatibility with earlier Python versions is required.

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/2209

First fixed release: 1.26.6

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

When NOT to Use This Fix

This fix should not be applied if compatibility with earlier Python versions is required.

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.
Add a TLS smoke test that performs a real handshake in CI (include CA bundle validation and hostname checks).
Alert on handshake failures by error string and endpoint to catch cert/CA changes quickly.

Version Compatibility Table

Version	Status
1.26.6	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

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