Among the features we're looking forward to seeing materialized during the F21 cycle include:
- Python 3 will become the default Python implementation over Python 2. The Py3 stack will also be upgraded from Python 3.3 to Python 3.4.
- The X.Org Server will run without root rights for better system security.
- Greater security by compiling packages with GCC using the -Werror=format-security switch to refuse compiling code that is vulnerable to a string format security flaw. It's part of an effort for Fedora to better secure its packages.
- Syslinux support will be added to U-Boot by default with pxelinux and extlinux support for simplified ARM booting.
- Allwinner "Sunxi" A10/A13/A20 ARM SoCs will be supported by Fedora ARM.
- Systemd changes ranging from the handling of the CUPS log to using systemd's journal to converting more cron jobs to systemd time units.
- Perhaps most exciting to us is the plans for great out-of-the-box OpenCL support. Fedora 21 may very well be the first operating system shipping with decent open-source OpenCL support in applications and by the open-source graphics drivers... The Gallium3D Clover still has a ways to mature for the Radeon/Nouveau drivers and for Intel there's the controversial Beignet project but hopefully by the time Fedora 21 is ready to ship the support and capabilities will be better and there will be more open-source applications on the desktop attempting to leverage GPGPU features.
Other planned Fedora 21 features can be found by our many Fedora 21 articles along with the official list on the Fedora Project Wiki. Fedora 21 is tentatively scheduled for a mid-October release but delays tend to be frequent for pushing out Fedora Linux.