It could have been me writing about an upgrade from 5.8 to 5.9 w/o reinstalling.
What I do now since VL7-Alpha. I have a partition /mnt/VL7new where I install
the new versions. Then I have another partition /mnt/VL7old. After installing
the new version I do preferably from a Live CD:
cp -au /mnt/VL7new/* /mnt/VL7old/
My working home directory has a separate partition which is the same as for
VL6. After the above command is completed I copy exssential files from
/mnt/VL7old/home/user to /mnt/VL6home/home/usr.
Has worked perfectly sofar and saves a lot of time since no reinstall of
files not included in the iso file.