I decided to upgrade my machines to Ubuntu Maverick Meerkat from Lucid Lynx. The steps are:

• In Software Sources, go to the updates page and set the ‘Check for Upgrades’ option to ‘Normal’
• Go to update manager and click upgrade

This worked on one machine and not the other. For the second machine it just kept saying “No new release found” no matter what I disabled or enabled in the config.

Eventually I found out I could use export DEBUG_UPDATE_MANAGER=true to debug update-manager on the command line and also do-distribution-upgrade and found that on this machine, part of update-manager wasn’t authenticating with the proxy properly (looks like a bug). I disabled the proxy (seems like I had to do it as root in synaptic as well as in the general gnome proxy settings) and ran update-manager again. Once it found the release, I was able to turn the proxy back on (to get faster download speeds) and start the upgrade.