macOS version support

Firedrake aims to work on all currently supported versions of macOS.

Developer notes

Once security updates stop getting released for a particular macOS version the default MACOSX_DEPLOYMENT_TARGET environment variable in firedrake-install should be changed.

A good indication that the install script may need to be modified is if macOS users start reporting install failures where the PETSc configure.log contains lines like the following:

ld: warning: object file (/opt/homebrew/Cellar/gcc/12.2.0/lib/gcc/current/gcc/aarch64-apple-darwin22/12/libgcc.a(fixhfti.o)) was built for newer macOS version (11.0) than being linked (10.15)

In this case indicating that MACOSX_DEPLOYMENT_TARGET should be updated from 10.15 to 11.0.

Sometimes users will report warnings like the following:

ld: warning: object file (...) was built for newer macOS version (XXX) than being linked (YYY)

where XXX is a much more modern version number (e.g. newer macOS version (14.0) than being linked (11.0)). This does not mean that the variable inside firedrake-install should be updated to 14.0, instead it should be updated to the oldest still supported version. Here for example this could be 12.0.