Upgrading from Ubuntu 6.06 LTS (Dapper Drake) to Ubuntu 8.04 LTS

Back-up all you data before proceeding.

# Prepare you system before the actual upgrade

lsb_release -a
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

# If running remotely, don't use ssh. See the previous tips for adding telnet to your mashine.
# The continue with the following lines (if logged in physically, skip following two cammands):
export DISPLAY=www.xxx.yyy.zzz

# On remote mashine
xhost +



# The following command opens a front-end. First press the button "check", then wait a few seconds, a button
"Upgrade to 8.04 LTS" should apear, press it and follow the instructions

sudo update-manager -d


# In case process breaks, you can try:
dpkg --configure -a

# Re-boot, check version again
lsb_release -a


References:
http://www.ubuntu.com/getubuntu/upgrading
http://www.ubuntu.com/getubuntu/upgrading#head-db224ea9add28760e373240f8239afb9b817f197