# ruff 0.16.3

- Product: ruff (https://whatsnew.fyi/product/ruff)
- Vendor: ruff
- Date: 2026-08-13
- Version: 0.16.3
- Original notes: https://github.com/astral-sh/ruff/releases/tag/0.16.3
- Permalink: https://whatsnew.fyi/product/ruff/releases/0.16.3

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **fixed** — Fix false negatives on negative numbers for PLR6104
- **added** — Add rule to replace while 1 with while True (UP048)
- **fixed** — Check keyword arguments for S602, S603, S607, S609
- **fixed** — Allow continue in finally on Python 3.8 for pylint
- **fixed** — Fix PLE1307 false positive with bools
- **fixed** — Fix false positives and negatives with %b format character for PLE1300 and PLE1307
- **fixed** — Improve handling of concatenated strings for PLE1300
- **changed** — Make np.chararray autofix backwards-compatible for NPY201
- **changed** — Enable PGO for Linux x86-64 Ruff releases
- **changed** — Enable PGO for Linux ARM64 Ruff releases
- **changed** — Enable PGO for Windows x86-64 Ruff releases
- **changed** — Enable PGO for macOS ARM64 Ruff releases
- **changed** — Reduce Expr size to 64 bytes
- **changed** — Hyperlink rule codes in ruff check --statistics output
- **changed** — Use mimalloc v3

##### Release Notes

Released on 2026-08-13.

###### Preview features

- \[`pylint`\] Fix false negatives on negative numbers (`PLR6104`) ([#27251](https://github.com/astral-sh/ruff/pull/27251))
- \[`pyupgrade`\] Add rule to replace `while 1` with `while True` (`UP048`) ([#27190](https://github.com/astral-sh/ruff/pull/27190))

###### Bug fixes

- \[`flake8-bandit`\] Also check keyword arguments (`S602`, `S603`, `S607`, `S609`) ([#27687](https://github.com/astral-sh/ruff/pull/27687))
- \[`pylint`\] Allow `continue` in `finally` on Python 3.8 ([#27626](https://github.com/astral-sh/ruff/pull/27626))
- \[`pylint`\] Fix `PLE1307` false positive with bools ([#27651](https://github.com/astral-sh/ruff/pull/27651))
- \[`pylint`\] Fix false positives and negatives with `%b` format character (`PLE1300`, `PLE1307`) ([#27560](https://github.com/astral-sh/ruff/pull/27560))
- \[`pylint`\] Improve handling of concatenated strings (`PLE1300`) ([#27659](https://github.com/astral-sh/ruff/pull/27659))

###### Rule changes

- \[`numpy`\] Make `np.chararray` autofix backwards-compatible (`NPY201`) ([#27527](https://github.com/astral-sh/ruff/pull/27527))

###### Performance

- Enable PGO for Linux x86-64 Ruff releases ([#27570](https://github.com/astral-sh/ruff/pull/27570))
- Enable PGO for Linux ARM64 Ruff releases ([#27574](https://github.com/astral-sh/ruff/pull/27574))
- Enable PGO for Windows x86-64 Ruff releases ([#27573](https://github.com/astral-sh/ruff/pull/27573))
- Enable PGO for macOS ARM64 Ruff releases ([#27572](https://github.com/astral-sh/ruff/pull/27572))
- Reduce `Expr` size to 64 bytes ([#27591](https://github.com/astral-sh/ruff/pull/27591))

###### CLI

- Hyperlink rule codes in `ruff check --statistics` output ([#27646](https://github.com/astral-sh/ruff/pull/27646))

###### Documentation

- \[`ruff`\] Also suggest `asyncio.TaskGroup` (`RUF006`) ([#27461](https://github.com/astral-sh/ruff/pull/27461))

###### Other changes

- Use mimalloc v3 ([#27586](https://github.com/astral-sh/ruff/pull/27586))

###### Contributors

- [@Andrej730](https://github.com/Andrej730)
- [@alonfaraj](https://github.com/alonfaraj)
- [@romero-deshaw](https://github.com/romero-deshaw)
- [@Avasam](https://github.com/Avasam)
- [@tjkuson](https://github.com/tjkuson)
- [@charliermarsh](https://github.com/charliermarsh)
- [@chirizxc](https://github.com/chirizxc)
- [@saberoueslati](https://github.com/saberoueslati)
- [@MichaReiser](https://github.com/MichaReiser)

##### Install ruff 0.16.3

###### Install prebuilt binaries via shell script

```sh
curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-installer.sh | sh
```

###### Install prebuilt binaries via powershell script

```sh
powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-installer.ps1 | iex"
```

##### Download ruff 0.16.3

|  File  | Platform | Checksum |
|--------|----------|----------|
| [ruff-aarch64-apple-darwin.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-aarch64-apple-darwin.tar.gz) | Apple Silicon macOS | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-aarch64-apple-darwin.tar.gz.sha256) |
| [ruff-x86_64-apple-darwin.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-x86_64-apple-darwin.tar.gz) | Intel macOS | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-x86_64-apple-darwin.tar.gz.sha256) |
| [ruff-aarch64-pc-windows-msvc.zip](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-aarch64-pc-windows-msvc.zip) | ARM64 Windows | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-aarch64-pc-windows-msvc.zip.sha256) |
| [ruff-i686-pc-windows-msvc.zip](https://releases.astral.sh/github/ruff/releases/download/0.16.3/ruff-i686-pc-windows-msvc.zip) | x86 Windows | [checksum](https://releases.astral.sh/github/ruff/releases/d

_[Truncated at 4000 characters — full notes: https://github.com/astral-sh/ruff/releases/tag/0.16.3]_