Latest Version: 4.83
Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet. It is freely available under the terms of the GNU General Public Licence. In style it is similar to Smail 3, but its facilities are more general. There is a great deal of flexibility in the way mail can be routed, and there are extensive facilities for checking incoming mail. Exim can be installed in place of Sendmail, although the configuration of Exim is quite different.
All versions of Exim previous to version 4.x are now obsolete and everyone is very strongly recommended to upgrade to a current release. The last 3.x release was 3.36. It is obsolete and should not be used.
The current version is 4.83
There may be beta versions available from the ftp sites in the Testing directory. Many people are using these without problems, but they are not recommended unless you are willing to work with beta software.