The latest Xcode 26 tools (or Command Line Tools, which we use for the official builds) do not support building for macOS versions older than 11.0 (see table).
(This is a build-time setting of the environment variable MACOSX_DEPLOYMENT_TARGET or equivalent compiler flags.)
macOS 11.0 (Big Sur) was released in Nov 2020 (Apple ended support in September 2023). The version before it was 10.15 (Catalina) released in October 2019 (end of support September 2022). (See table.)
We have not been maintaining the minimum version setting for many years (it's currently set to 10.9 in the nightly build scripts, even though Xcode has only supported 10.13 or later for several years (Xcode 14-16)). Setting to a value lower than the toolchain supports does not cause an error (wish it did), but creates binaries that may purport to run in older versions of macOS than they actually do.
Aside from the fact that the only practical way these days is to stay up to date with the latest versions of everything, we also need macOS 10.14 for C++17 (10.15 for std::filesystem), so setting to 11.0 seems practical. (11.0 is also the first macOS version supporting arm64.)
Note: macOS version numbers skipped from 10.15 to 11 and from 15 to 26; starting with 26, the macOS and Xcode (and iOS, etc.) versions match the next calendar year ("vehicle model year").
The latest Xcode 26 tools (or Command Line Tools, which we use for the official builds) do not support building for macOS versions older than 11.0 (see table).
(This is a build-time setting of the environment variable
MACOSX_DEPLOYMENT_TARGETor equivalent compiler flags.)macOS 11.0 (Big Sur) was released in Nov 2020 (Apple ended support in September 2023). The version before it was 10.15 (Catalina) released in October 2019 (end of support September 2022). (See table.)
We have not been maintaining the minimum version setting for many years (it's currently set to 10.9 in the nightly build scripts, even though Xcode has only supported 10.13 or later for several years (Xcode 14-16)). Setting to a value lower than the toolchain supports does not cause an error (wish it did), but creates binaries that may purport to run in older versions of macOS than they actually do.
Aside from the fact that the only practical way these days is to stay up to date with the latest versions of everything, we also need macOS 10.14 for C++17 (10.15 for
std::filesystem), so setting to 11.0 seems practical. (11.0 is also the first macOS version supporting arm64.)Note: macOS version numbers skipped from 10.15 to 11 and from 15 to 26; starting with 26, the macOS and Xcode (and iOS, etc.) versions match the next calendar year ("vehicle model year").