Our [wiki:Dependencies dependencies] policy is simple. For runtime dependencies: * We support each major Debian version until one year after the release of the next major version. * We support each Ubuntu LTS until one year after the release of the next Ubuntu LTS. In effect, it means that WebKit updates will be buildable for any particular distribution for roughly three years. (We will consider lengthening this support period up to five years, for runtime dependencies only, if requested by a distribution that intends to provide WebKit security updates during this time.) This policy applies both to the default toolchain and the runtime dependencies to ensure smooth updates for users. But the requirement of "one year after the release" does not apply to the default toolchain (only to the runtime dependencies). On that extra year of support, a compiler other than the default one in an otherwise-supported distribution may be required to build. For information on why the build toolchain is supported for less time than runtime dependencies, see [[GCCRequirement]].