old rpms after upgrade

[Peter J. Stieber]

I have an x86_64 I have upgraded from Fedora 6 -> 7 -> 8.  I upgrade 
using DVDs generated from ISO images provided with each new 
distribution.  I'm worried about left over rpms from prior installs that 
may eventually cause problems.

$ rpm -qa | grep fc6
enchant-1.3.0-1.fc6
dmidecode-2.7-1.26.1.fc6
keyutils-libs-1.2-2.fc6
mcelog-0.7-1.22.fc6
xorg-x11-filesystem-7.1-2.fc6
libavc1394-0.5.3-1.fc6
keyutils-libs-1.2-2.fc6
keyutils-libs-devel-1.2-2.fc6
gnuchess-5.07-10.fc6
tux-3.2.18-9.fc6

There are others for fc7.

Why does this happen?

What should I do about it?

Pete