If Ubuntu 15.10 has been officially released and you are lucky enough to see the upgrade notification, then everything is very simple. Just click the ???Upgrade??? button to proceed and wait for the tool to gather all the information need to perform the upgrade. At this point, you will be notified whether your computer is compatible with Ubuntu 15.10 or not, any third-party PPAs will be disabled during the upgrade process, which will take a few hours, depending on your Internet connection and the specs of your PC.