Upgrade Ubuntu From 11.10 to 12.04
To upgrade from Ubuntu 11.10 on a server system, follow the steps listed below:
Install the update-manager-core package (if it is not already installed).
Run sudo do-release-upgrade to launch the upgrade tool. Follow the on-screen instructions. Note that the server upgrade is now more robust and will utilize GNU screen and automatically re-attach in case of dropped connection problems, for example.
So, type the following commands:
sudo apt-get install update-manager-core sudo do-release-upgrade sudo apt-get update && sudo apt-get upgrade
Check version after upgrade
Upgrade from Ubuntu 12.04 LTS to 12.10
First of all we have to check if the new version is available. Open a terminal Ctrl+Alt+T and give this command.
This command will check if the new version is available from the servers and will return the result.
If the version is available we can proceed.
If the version is not available then check one thing. Open this file
gksudo gedit /etc/update-manager/release-upgradesand see if Prompt is equal to normal
Prompt=normal, If its not , then change it and after you save the file run in terminal
sudo apt-get update do-release-upgrade -c