From Fedora Project Wiki
Updates to GNOME and GNOME Software
Several major changes related to the GNOME desktop environment have been included in Fedora 21. These changes include updating GNOME to version 3.12, many improvements to the GNOME Software application installer, and support for the Wayland display server. See https://fedoraproject.org/wiki/Documentation_Desktop_Beat for details. (NOTE: xref)