mu/mu4e are known to work on a wide variety of Unix- and Unix-like
systems, including many Linux distributions, OS X and FreeBSD. Emacs 26.3 or
higher is required, as well as Xapian and
GMime.
mu has optional support for the Guile (Scheme) programming language (version
3.0 or higher). There are also some GUI-toys, which require GTK+ 3.x and Webkit.
If you intend to compile mu yourself, you need to have the typical
development tools, such as C and C++17 compilers (both gcc and
clang work), meson and make, and the development
packages for GMime 3.x, GLib and Xapian. Optionally, you also need the
development packages for GTK+, Webkit and Guile.