[CentOS] Using yum variable $releasever reports 1

Hi,

I have an old server that originally was a RedHat 8 server. Then I
upgraded to RedHat 9, then Tao Linux 1 and last to CentOS 3 when tao was
discontinued. Yes I know that this was probably not the smartest thing in
the world but now this is the case and I don't want to reinstall it.

Now the question. In yum.conf I have distroverpkg=redhat-release and cat
/etc/redhat-release gives:

CentOS release 3.7 (Final)

But when I run yum update the release reported back is 1.0
yum update
Gathering header information file(s) from server(s)
Server: CentOS-1.0 - Addons
Server: CentOS-1.0 - Base

Until now I have manually changed yum.conf and replaced $relesever with
whatever version I had but why is $relesever replaced with 1.0 ?

      Jens