As of 23rd of June 2015, Fedora 20 has reached its end of life for updates and support. No further updates, including security updates, will be available for Fedora 20. A previous reminder was sent on 27th of May [0].
Fedora 21 will continue to receive updates until approximately one month after the release of Fedora 23. The maintenance schedule of Fedora releases is documented on the Fedora Project wiki [1]. The Fedora Project wiki also contains instructions [2] on how to upgrade from a previous release of Fedora to a version receiving updates.
Kevin
[0] https://lists.fedoraproject.org/pipermail/announce/2015-May/003267.html [1] https://fedoraproject.org/wiki/Fedora_Release_Life_Cycle#Maintenance_Schedul... [2] http://fedoraproject.org/wiki/DistributionUpgrades
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