0.16.5

## Release Notes

Released on 2026-08-27.

### Preview features

- Allow rules without codes ([#28049](https://github.com/astral-sh/ruff/pull/28049))
- Introduce category selectors ([#27666](https://github.com/astral-sh/ruff/pull/27666))
- Update preview default rules and categories ([#27877](https://github.com/astral-sh/ruff/pull/27877))

### Bug fixes

- \[`flake8-async`\] Detect blocking generic HTTP requests (`ASYNC210`) ([#28024](https://github.com/astral-sh/ruff/pull/28024))
- \[`flake8-datetimez`\] Allow timezone-safe `strptime` chains (`DTZ007`) ([#28023](https://github.com/astral-sh/ruff/pull/28023))
- \[`flake8-simplify`\] Respect side effects in `lambda` defaults (`SIM401`) ([#28000](https://github.com/astral-sh/ruff/pull/28000))

### Server

- Fix duplicated "of" in `ClientOptions` doc comment ([#27978](https://github.com/astral-sh/ruff/pull/27978))

### Documentation

- Document rule acceptance guidelines ([#27910](https://github.com/astral-sh/ruff/pull/27910))
- Document the new category selectors ([#27906](https://github.com/astral-sh/ruff/pull/27906))

### Contributors

- [@AlexWaygood](https://github.com/AlexWaygood)
- [@sharkdp](https://github.com/sharkdp)
- [@jelle-openai](https://github.com/jelle-openai)
- [@charliermarsh](https://github.com/charliermarsh)
- [@ntBre](https://github.com/ntBre)
- [@aarushkandukoori](https://github.com/aarushkandukoori)

## Install ruff 0.16.5

### Install prebuilt binaries via shell script

```sh
curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-installer.sh | sh
```

### Install prebuilt binaries via powershell script

```sh
powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-installer.ps1 | iex"
```

## Download ruff 0.16.5

|  File  | Platform | Checksum |
|--------|----------|----------|
| [ruff-aarch64-apple-darwin.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-apple-darwin.tar.gz) | Apple Silicon macOS | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-apple-darwin.tar.gz.sha256) |
| [ruff-x86_64-apple-darwin.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-apple-darwin.tar.gz) | Intel macOS | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-apple-darwin.tar.gz.sha256) |
| [ruff-aarch64-pc-windows-msvc.zip](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-pc-windows-msvc.zip) | ARM64 Windows | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-pc-windows-msvc.zip.sha256) |
| [ruff-i686-pc-windows-msvc.zip](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-i686-pc-windows-msvc.zip) | x86 Windows | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-i686-pc-windows-msvc.zip.sha256) |
| [ruff-x86_64-pc-windows-msvc.zip](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-pc-windows-msvc.zip) | x64 Windows | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-pc-windows-msvc.zip.sha256) |
| [ruff-aarch64-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-unknown-linux-gnu.tar.gz) | ARM64 Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-i686-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-i686-unknown-linux-gnu.tar.gz) | x86 Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-i686-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-powerpc64-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-powerpc64-unknown-linux-gnu.tar.gz) | PPC64 Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-powerpc64-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-powerpc64le-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-powerpc64le-unknown-linux-gnu.tar.gz) | PPC64LE Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-powerpc64le-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-riscv64gc-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-riscv64gc-unknown-linux-gnu.tar.gz) | RISCV Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-riscv64gc-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-s390x-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-s390x-unknown-linux-gnu.tar.gz) | S390x Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-s390x-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-x86_64-unknown-linux-gnu.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-unknown-linux-gnu.tar.gz) | x64 Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-unknown-linux-gnu.tar.gz.sha256) |
| [ruff-armv7-unknown-linux-gnueabihf.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-armv7-unknown-linux-gnueabihf.tar.gz) | ARMv7 Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-armv7-unknown-linux-gnueabihf.tar.gz.sha256) |
| [ruff-aarch64-unknown-linux-musl.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-unknown-linux-musl.tar.gz) | ARM64 MUSL Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-aarch64-unknown-linux-musl.tar.gz.sha256) |
| [ruff-i686-unknown-linux-musl.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-i686-unknown-linux-musl.tar.gz) | x86 MUSL Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-i686-unknown-linux-musl.tar.gz.sha256) |
| [ruff-x86_64-unknown-linux-musl.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-unknown-linux-musl.tar.gz) | x64 MUSL Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-x86_64-unknown-linux-musl.tar.gz.sha256) |
| [ruff-arm-unknown-linux-musleabihf.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-arm-unknown-linux-musleabihf.tar.gz) | ARMv6 MUSL Linux (Hardfloat) | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-arm-unknown-linux-musleabihf.tar.gz.sha256) |
| [ruff-armv7-unknown-linux-musleabihf.tar.gz](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-armv7-unknown-linux-musleabihf.tar.gz) | ARMv7 MUSL Linux | [checksum](https://releases.astral.sh/github/ruff/releases/download/0.16.5/ruff-armv7-unknown-linux-musleabihf.tar.gz.sha256) |

## Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the [GitHub CLI](https://cli.github.com/manual/gh_attestation_verify):
```sh
gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ruff
```

You can also download the attestation from [GitHub](https://github.com/astral-sh/ruff/attestations) and verify against that directly:
```sh
gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>
```