With the recent release of Fedora 25, Fedora 23 will officially enter End Of Life (EOL) status on December 20th, 2016. After December 20th, all packages in the Fedora 23 repositories will no longer receive security, bugfix, or enhancement updates, and no new packages will be added to the Fedora 23 collection.
Looking back at Fedora 23
Fedora 23 was released in early November 2015, and during this time the Fedora Community have published over 10 000 updates to the Fedora 23 Repositories. Fedora 23 released with version 4.2 of the Linux kernel, and Fedora Workstation featured version 3.18 of GNOME. LibreOffice version 5 also made it’s first appearance in Fedora 23, and Fedora 23 also introduced the brand new Cinnamon spin.
About the Fedora Release Cycle
The Fedora Project provides updates for a particular release up until a month after the second subsequent version of Fedora is released. For example, updates for Fedora 24 will continue until one month after the release of Fedora 26, and Fedora 25 will continue to be supported up until one month after the release of Fedora 27.
The Fedora Project wiki contains more detailed information about the entire Fedora Release Life Cycle, from development to release, and the post-release support period.