How To Update exim using a source rpm (src.rpm)

In this how-to, we'll describe how to compile a new version of th exim src.rpm file in order to update exim.
We'll use exim for an system for the example, so if you need a new/older version, just replace all instances of that version with the version you want (assuming we have it on our server).

wget http://files.directadmin.com/services/da_exim-4.84-1.src.rpm
rpmbuild --rebuild --force da_exim-4.84-1.src.rpm
rpm -Uvh /usr/src/redhat/RPMS/x86_64/da_exim-4.84-1.x86_64.rpm
/etc/init.d/exim restart

If needed, use the --nodeps and/or --force options with the rpm command.

If you get errors like:

error: unpacking of archive failed on file /usr/src/redhat/SOURCES/da_exim-4.84.tar.gz;54602f6b: cpio: MD5 sum mismatch
error: da_exim-4.84-1.src.rpm cannot be installed

then you can go about it another way, eg:

wget http://files.directadmin.com/services/da_exim-4.84-1.src.rpm
rpm --nomd5 -ivh da_exim-4.84-1.src.rpm
cd /usr/src/redhat/SPECS
rpmbuild -bb exim.spec
rpm -Uvh /usr/src/redhat/RPMS/x86_64/da_exim-4.84-1.x86_64.rpm
/etc/init.d/exim restart