Supported build targets ======================= .. role:: strikethrough There are three tiers of **supported Firefox build targets** at this time. These tiers represent the shared engineering priorities of the Mozilla project. .. note:: Sheriffs are in charge of monitoring the tree. Their definition for tiers is for automation jobs, which tells a developer what is expected of them when they land code. This document is about the tiers of supported build targets, which tells a person compiling/using Firefox what they can expect from Mozilla. See the `job tier definition `__ for more information. .. _tier-1: The term **"Tier-1 platform"** refers to those platforms - CPU architectures and operating systems - that are the primary focus of Firefox development efforts. Tier-1 platforms are fully supported by Mozilla's `continuous integration processes `__ and the :ref:`Try Server`. Any proposed change to Firefox on these platforms that results in build failures, test failures, performance regressions or other major problems **will be reverted immediately**. The **Tier-1 Firefox platforms** and their supported compilers are: - Android on Linux x86, x86-64, ARMv7 and ARMv8-A (clang) - Linux/x86 and x86-64 (gcc and clang) - macOS 10.12 and later on x86-64 and AArch64 (clang) - Windows/x86, x86-64 and AArch64 (clang-cl) Prior to Firefox 63, Windows/x86 and Windows/x86-64 relied on the MSVC compiler; from **Firefox 63 onward MSVC is not supported**. Older 32-bit x86 CPUs without SSE2 instructions such as the Pentium III and Athlon XP are also **not considered Tier-1 platforms, and are not supported**. Note also that while Windows/x86 and ARM/AArch64 are supported *as build targets*, it is not possible to build Firefox *on* Windows/x86 or Windows/AArch64 systems. .. _tier-2: **Tier-2 platforms** are actively maintained by the Mozilla community, though with less rigorous requirements. Proposed changes resulting in breakage or regressions limited to these platforms **may not immediately result in reversion**. However, developers who break these platforms are expected to work with platform maintainers to fix problems, and **may be required to revert their changes** if a fix cannot be found. The **Tier-2 Firefox platforms** and their supported compilers are: - Linux/AArch64 (clang) - Windows/x86 (mingw-clang) - maintained by Tom Ritter and Jacek Caban - - *Note that some features of this platform are disabled, as they require MS COM or the w32api project doesn't expose the necessary Windows APIs.* .. _tier-3: **Tier-3 platforms** have a maintainer or community which attempt to keep the platform working. These platforms are **not supported by our continuous integration processes**, and **Mozilla does not routinely test on these platforms**, nor do we block further development on the outcomes of those tests. At any given time a Firefox built from mozilla-central for these platforms may or may not work correctly or build at all. **Tier-3 Firefox platforms** include:  - Linux on various CPU architectures including ARM variants not listed above, PowerPC, and x86 CPUs without SSE2 support - maintained by various Linux distributions - FreeBSD/x86, x86-64, Aarch64 (clang) - maintained by Jan Beich - OpenBSD/x86, x86-64 (clang) - maintained by Landry Breuil - NetBSD/x86-64 (gcc) - maintained by David Laight - Solaris/x86-64, sparc64 (gcc) - maintained by Petr Sumbera - :strikethrough:`Windows/x86-64 (mingw-gcc)` - Unsupported due to requirements for clang-bindgen If you're filing a bug against Firefox on a Tier-3 platform (or any combination of OS, CPU and compiler not listed above) please bear in mind that Mozilla developers do not reliably have access to non-Tier-1 platforms or build environments. To be actionable bug reports against non-Tier-1 platforms should include as much information as possible to help the owner of the bug determine the cause of the problem and the proper solution. If you can provide a patch, a regression range or assist in verifying that the developer's patches work for your platform, that would help a lot towards getting your bugs fixed and checked into the tree.