Merge pull request #19641 from Homebrew/support_tiers

Add Support Tiers documentation

Author: MikeMcQuaid

docs/Support-Tiers.md

@@ -0,0 +1,110 @@
+---
+last_review_date: "2025-03-28"
+---
+
+# Support Tiers
+
+Homebrew has three support tiers.
+These set expectations for how well Homebrew will run on a given configuration.
+
+## Tier 1
+
+A Tier 1 supported configuration is one in which:
+
+- you're setup to get the best experience using Homebrew
+- we will aim to fix reproducible bugs affecting this configuration
+- we will not output warnings about running on this configuration
+- we have CI coverage for automated testing and building bottles for this configuration
+- your support is best met through Homebrew's issue trackers
+- Homebrew may block merging a PR if it doesn't build properly on this configuration
+
+### macOS
+
+For Tier 1 support, Homebrew on macOS must be all of:
+
+- running on official Apple hardware (e.g. not a "Hackintosh" or VM)
+- running a version of macOS supported by Apple on that hardware (e.g. not using OpenCore Legacy Patcher)
+- running a version of macOS with Homebrew CI coverage (i.e. the latest stable or prerelease version, two preceding versions)
+- installed in the default prefix (i.e. `/opt/homebrew` on Apple Silicon, `/usr/local` on Intel x86_64)
+- running on a supported architecture (i.e. Apple Silicon or Intel x86_64)
+- not building official packages from source
+- installed on your Mac's built-in hard-drive (i.e. not external/removable storage)
+- you have `sudo` access on your system
+- the Xcode Command Line Tools are installed and fully up-to-date
+
+### Linux
+
+For Tier 1 support, Homebrew on Linux must be all of:
+
+- running on Ubuntu or a Homebrew-provided Docker image
+- have a system `glibc` >= 2.35
+- if running Ubuntu, running an Ubuntu version in "standard support": <https://ubuntu.com/about/release-cycle>
+- installed in the default prefix (i.e. `/home/linuxbrew/.linuxbrew`)
+- running on a supported architecture (i.e. Intel x86_64)
+- not building official packages from source
+- you have `sudo` access on your system
+
+## Tier 2
+
+A Tier 2 supported configuration is one in which any of:
+
+- you get a subpar but potentially still usable experience using Homebrew
+- we review PRs that fix bugs affecting this configuration but will not aim to fix bugs
+- we will output `brew doctor` warnings running on this configuration
+- we have partial CI coverage for testing and building bottles for this configuration so some bottles will not be available
+- we will close issues only affecting this configuration
+- your support is best met through Homebrew's Discussions
+
+Tier 2 configurations include:
+
+- macOS prereleases before we state they are Tier 1 (e.g. in March 2025, macOS 16, whatever it ends up being called)
+- Linux versions where a system `glibc` < 2.35 (but still >= 2.13), so the Homebrew `glibc` formula is automatically installed
+- using official packages that need to be built from source due to installing Homebrew outside the default prefix
+  (i.e. `/opt/homebrew` on Apple Silicon, `/usr/local` on Apple Intel x86_64, `/home/linuxbrew/.linuxbrew` for Linux)
+- running on a not-yet-supported architecture (i.e. Linux ARM64/AARCH64)
+
+## Tier 3
+
+A Tier 3 supported configuration is one in which:
+
+- you get a poor but not completely broken experience using Homebrew
+- we strongly recommend migrating to a Tier 1 or 2 configuration or a non-Homebrew tool
+- we will only review PRs with a very high bar: any changes must be proven by the author to fix (not work around) an issue and not come with high maintainability costs (no patches)
+- we will generally not aim to fix bugs ourselves affecting this configuration
+- we may intentionally regress functionality on this configuration if it e.g. improves things for other configuration
+- we will output noisy warnings running on this configuration
+- we are lacking any CI coverage for testing or building bottles for this configuration so few bottles will be available
+- we will close without response issues only affecting this configuration
+- your support is best met through Homebrew's Discussions
+
+Tier 3 configurations include:
+
+- macOS versions for which we no longer provide CI coverage and Apple no longer provides most security updates for (e.g. as of March 2025, macOS Monterey/12 and older)
+- building official packages from source when binary packages are available
+- installing Homebrew outside the default prefix (i.e. `/opt/homebrew` on Apple Silicon, `/usr/local` on Apple Intel x86_64, `/home/linuxbrew/.linuxbrew` for Linux)
+- installing formulae using `--HEAD`
+- installing deprecated or disabled formulae
+
+## Unsupported
+
+An unsupported configuration is one in which:
+
+- Homebrew will refuse to run at all without third-party patching
+- You must migrate to another tool (e.g. Tigerbrew, MacPorts, Linux system package managers etc.)
+
+Tier 3 configurations include:
+
+- FreeBSD
+- macOS 10.6
+- Beowulf clusters
+- Nokia 3210s
+- CPUs built inside of Minecraft
+- toasters
+
+## Unsupported Software
+
+Note that all packages installed from third-party taps outside of the Homebrew GitHub organisation are unsupported by default.
+
+We may assist the maintainers/contributors/developers of such packages to fix bugs with the Homebrew formula/cask/tap system, but we are not responsible for resolving issues when using that software.
+
+Bugs that only manifest when using third-party formulae/casks may be closed.

docs/index.md

@@ -9,6 +9,7 @@ last_review_date: "2025-02-08"
 - [`brew` manual page (command documentation)](Manpage.md)
 - [Homebrew Blog (news on major updates)](https://brew.sh/blog/)
 - [Installation](Installation.md)
+- [Support Tiers](Support-Tiers.md)
 - [Troubleshooting](Troubleshooting.md)
 - [FAQ (Frequently Asked Questions)](FAQ.md)
 - [Common Issues](Common-Issues.md)