The Fedora Project keeps three versions of the OS active at any given time — the current release, the release before that, and a new one in development. With last month’s release of Fedora 22 and Fedora 23 development underway, it’s time to bid a fond farewell to Fedora 20.
That release will reach end of life on June 23rd, 2015. No further updates will be pushed out beyond that point.