14 DAY TRIAL // Fedora 21 hasn't been released just yet, but the developers are already making plans for subsequent releases that will be made in the future. Right now, they are looking for a possible implementation of the Btrfs file system instead of the current Ext4.
Very few operating systems have adopted Btrfs as default. The most prominent one is OpenSuSE, but that seems to be the exception and not the rule. If Fedora manages to pull this off, it just might be the push that the Linux community needs to advance beyond Ext4.
"My plan is to push for F23, I'm still wrapping up some balance bugs and some other issues we've found at work and then this will be my next priority. Suse benefits from having a narrow 'supported' criteria, like only use it with lots of space and don't use any of the RAID stuff, plus they have two kernel guys on it and Dave Sterba who is now in charge of btrfs-progs. We will get there, and when we do it will be less painful than its going to be for Suse since they will have fixed it all for us," said Fedora developer Josef Bacik.
A new Fedora release is on its way, version 21, and the first Alpha in the series was just made available. It will be a very long time until we'll see Fedora 23 out the door, and not even then the adoption of Btrfs is something sure.