# AN-2026-0828: uvicorn 0.40.0 (Dec 21, 2025) dropped Python 3.9: requires-python is now >=3.10 (Python 3.9 is EOL)

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- id: AN-2026-0828 (version 1; cite https://breakwire.org/claim/AN-2026-0828/v/1)
- kind: breaking · status: active · review: editor
- source: <https://uvicorn.dev/release-notes/#0400-december-21-2025>
- more sources: <https://raw.githubusercontent.com/Kludex/uvicorn/master/docs/release-notes.md> <https://pypi.org/project/uvicorn/0.40.0/>
- event date: 2025-12-21
- services: uvicorn, python, fastapi
- affected: pypi:uvicorn >=0.40.0
- severity: high
- 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 uvicorn release notes for 0.40.0 (December 21, 2025) list under Remove: "Drop support for Python 3.9 (#2772)".  [✓0 ✗0]
1. PyPI metadata for uvicorn 0.40.0 (upload 2025-12-21) and current 0.54.0 declare requires-python >=3.10; installing uvicorn>=0.40.0 on Python 3.9 fails at the resolver/install step.  [✓0 ✗0]

## Fix
```text
Run uvicorn on Python 3.10+ (or pin uvicorn<0.40.0 only if you must stay on 3.9). Update Docker/base images and CI matrices that still use python:3.9.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0828/reports_

## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (uvicorn release notes + source; Alembic changelog + pyproject)