

You should always run a supported release of Ubuntu in order to receive security bug fixes. Renewing the Installation without formatting the partitions (in contrast to upgrading), will also keep the personal data and configurations under /home but will renew all system settings under /etc as well as the default set of installed packages. For example, to upgrade from Ubuntu 16.10 to Ubuntu 17.10, first upgrade to 17.04, then upgrade 17.04 to 17.10. If you wish to 'skip' a version, you can back up your data and do a fresh installation, or progressively upgrade to each successive version. Ubuntu 16.04 to Ubuntu 16.10) or from one LTS release to the next (e.g.

To avoid damaging your running system, upgrading should only be done from one release to the next release (e.g.

An example of this would be going from Ubuntu 17.10 to Ubuntu 18.04 LTS. An upgrade is the process of going from an earlier version of Ubuntu to a newer version of Ubuntu with an installed system.
