●Change8

Migrating to Black 25.12.0

Version 25.12.0 introduces 1 breaking change. This guide details how to update your code.

Released: 12/8/2025

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Breaking Changes
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Migration Steps
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Affected Symbols

Breaking Changes

●Issue #1

Black no longer supports running with Python 3.9; upgrade your environment to Python 3.10 or newer.

Migration Steps

  1. 1
    If you rely on Python 3.9, pin Black to a version prior to 25.12.0.
  2. 2
    Review any custom `# fmt: skip` usage; the handling of skips has been corrected and may affect formatting outcomes.
  3. 3
    Update GitHub Action workflows to use the new `output-file` input if you need formatter output captured as an artifact.
  4. 4
    If you distribute Black binaries, note that arm64 Windows wheels are now available; adjust CI/CD pipelines accordingly.

Release Summary

Black 25.12.0 drops Python 3.9 support, adds several bug fixes, introduces draft 2026 style, and enhances packaging and GitHub Action integration.

Need More Details?

View the full release notes and all changes for Black 25.12.0.

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