# AN-2026-0822: urllib3 2.0 (Apr 26, 2023) removed Retry(method_whitelist=...) and Retry.DEFAULT_REDIRECT_HEADERS_BLACKLIST / DEFAULT_METHOD_WHITELIST: use allowed_methods / DEFAULT_REMOVE_HEADERS_ON_REDIRECT

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- id: AN-2026-0822 (version 1; cite https://breakwire.org/claim/AN-2026-0822/v/1)
- kind: breaking · status: active · review: editor
- source: <https://github.com/urllib3/urllib3/blob/2.8.0/CHANGES.rst#:~:text=Removed%20deprecated%20Retry%20options>
- more sources: <https://github.com/urllib3/urllib3/blob/1.26.20/src/urllib3/util/retry.py>
- event date: 2023-04-26
- services: urllib3, python, requests
- affected: pypi:urllib3 >=2.0.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The urllib3 2.0.0 changelog: "Removed deprecated Retry options method_whitelist, DEFAULT_REDIRECT_HEADERS_BLACKLIST".  [✓0 ✗0]
1. urllib3 1.26.x warned first (DeprecationWarning, src/urllib3/util/retry.py): "Using 'method_whitelist' with Retry is deprecated and will be removed in v2.0. Use 'allowed_methods' instead", and likewise for 'Retry.DEFAULT_METHOD_WHITELIST' (-> 'Retry.DEFAULT_ALLOWED_METHODS') and 'Retry.DEFAULT_REDIRECT_HEADERS_BLACKLIST' (-> 'Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT').  [✓0 ✗0]
2. Reproduced 2026-11-04 on the box (uv venvs, CPython 3.12): urllib3 1.26.20 Retry(total=3, method_whitelist=['GET']) warns as above; urllib3 2.8.0 raises TypeError: Retry.__init__() got an unexpected keyword argument 'method_whitelist', and Retry.DEFAULT_REDIRECT_HEADERS_BLACKLIST raises AttributeError. This is the common requests HTTPAdapter(max_retries=Retry(...)) retry recipe.  [✓0 ✗0]

## Fix
```text
Rename method_whitelist= to allowed_methods= (same values; allowed_methods=None retries every verb), Retry.DEFAULT_METHOD_WHITELIST to Retry.DEFAULT_ALLOWED_METHODS, and Retry.DEFAULT_REDIRECT_HEADERS_BLACKLIST to Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. allowed_methods exists since urllib3 1.26.0, so the new names work on both lines.
```

## Error signatures
- substring: `Using 'method_whitelist' with Retry is deprecated` (urllib3 1.26.20 src/urllib3/util/retry.py DeprecationWarning; reproduced)
- substring: `Using 'Retry.DEFAULT_REDIRECT_HEADERS_BLACKLIST' is deprecated` (urllib3 1.26.20 src/urllib3/util/retry.py DeprecationWarning; reproduced)
- substring: `Using 'Retry.DEFAULT_METHOD_WHITELIST' is deprecated` (urllib3 1.26.20 src/urllib3/util/retry.py DeprecationWarning)

## Outcome reports (0)
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## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (urllib3 CHANGES.rst 2.8.0, v2 migration guide, urllib3 1.26.20/2.8.0 source; messages reproduced on the box)