Exim is still under active development; the version of Exim included in
Linux distributions is probably not the latest release. If you need a
feature or a bugfix found in a later release, you have to obtain a
copy of the source code and compile it yourself. The latest release can be
found via Exim's web page at
Linux is one of the many operating systems supported by the Exim source. To
compile Exim for Linux, you should edit the src/EDITME
file and put the result in a file called Local/Makefile.
There are comments in src/EDITME that tell you what the
various settings are used for. Then run make. See the Exim
manual for detailed information on building Exim from source.