You are about to upgrade to a version of Ubuntu that is no longer supported.
This release of Ubuntu is no longer supported by Canonical. The support timeframe is between 18 month and 5 years after the initial release. You will not receive security updates or critical bugfixes. See http://www.ubuntu.com/releaseendoflife for details.
It is still possible to upgrade this version and eventually you will be able to upgrade to a supported release of Ubuntu.
Alternatively you may want to consider to reinstall the machine to the latest version, for more information on this, visit: http://www.ubuntu.com/desktop/get-ubuntu
For pre-installed system you may want to contact the manufacturer for instructions.