Fedora 16 has been discontinued
As of 12 February 2013, Fedora 16 has reached its end of life for updates and support. No further updates, including security updates, will be available for Fedora 16. A previous reminder was sent on May 31st.Fedora 16 End of Life
Fedora 17 will continue to receive updates until approximately one month after the release of Fedora 19. The maintenance schedule of Fedora releases is documented on the Fedora Project wiki. The Fedora Project wiki also contains instructions [2] on how to upgrade from a previous release of Fedora to a version receiving updates.