Heho,
> I am running Scientific Linux 6.0, which comes with Apache 2.2.15.
> I need to upgrade it to 2.2.21.
Please keep in mind that a manual installation will result in you having
to keep track of security updates.

> I tried the following:
> - yum remove httpd*
> - take the httpd-2.2.21.tar.gz, build it and install httpd,suexec,apxs
> - then config yum to exclude httpd*
> - run yum updates
> I get errors because it requires httpd-mmn (it is the magic number, I
> understand).
> Is it possible to get the httdp-mmn in synch? I can't see this in the
> apache package.
I would personally recommend creating a local package of apache 2.2.21
and then using yum localinstall. I will take a look at that anyway.

With best regards,
Tobias