I’m in the process of testing some software and wanted to upgrade a server I have with Ubuntu 6.06 LTS (Dapper) to 7.04 (Feisty)
The steps are simple, but aren’t documented on Ubuntu’s website (since we’re upgrading two version levels.)

The steps are pretty simple (all done as root):

  1. edit: /etc/apt/sources.list replace dapper with edgy everywhere in tha tfile
  2. run: apt-get update
  3. run: apt-get dist-upgrade and follow the prompts being careful of which config files you choose to replace
  4. reboot: shutdown -r now
  5. run: apt-get install update-manager-core
  6. run: do-release-upgrade and follow the prompts. I was able to upgrade over ssh without trouble

The entire process took me about an hour to complete. The do-release-upgrade command will prompt you to reboot at the end.