As of 09 December 2011, Fedora 14 has reached its end of life for updates and support. No further updates, including security updates, will be available for Fedora 14. A previous reminder was sent on November 8th .
Fedora 15 will continue to receive updates until approximately one month after the release of Fedora 17. The maintenance schedule of Fedora releases is documented on the Fedora Project wiki . The Fedora Project wiki also contains instructions  on how to upgrade from a previous release of Fedora to a version receiving updates.