Upgrade Linux Ubuntu from 14.10 to 15.04

[hubsinfo]

Ubuntu Desktops 14.10 to 15.04 (Recommended)

You can easily upgrade over the network with the following procedure.
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• Run the update-manager application from the Unity Dash or a command line
  
• In Update Manager, click the Settings... button, and enter your password to start the Software Sources application.
  
• Select the sub menu Updates from the Software Sources application.
  
• Confirm the "Notify me of a new Ubuntu version:" option is set to "For any new version", and change it if otherwise.
  
• Close the Software Sources application and return to Update Manager.
  
• In Update Manager, click the Check button to check for new updates.
  
• If there are any updates to install, use the Install Updates button to install them, and press Check again after that is complete.
  
• A message will appear informing you of the availability of the new release.
  
• Click Upgrade.
  
• Follow the on-screen instructions.