The Hypervisor is developed by a world-wide community of individuals, researchers and employees of companies and that follow the Xen Project Governance process based on openness, transparency and meritocracy. The project is supported by the Xen Project Advisory Board made up of project member companies that fund the Xen Project. You can find a recent contribution breakdown in the Xen Project 4.4 and Xen Project 4.3 Contribution Acknowledgments.
Introduction to the Hypervisor
What's in Xen Project 4.4
In 2014, we released Xen Project 4.4.0. You can find more information on Xen Project 4.4 in the Feature List, Release Notes and Man Pages. Xen Project 4.4 software can be downloaded from the Xen Project 4.4 download pages.
Xen Project 4.4 Features and Futures
Xen Project Releases are developed on a 9 months release cadence and follows the process outlined here.
Getting the Hypervisor
Sources for Xen Project Binaries
You can get recent binaries as packages from most Linux and Unix distributions, both open source and commercial. Some Linux distributions deliver Xen Project software as a LiveCD, that you can use to easily test the hypervisor.
The Xen Hypervisor is licensed under the GNU General Public License (GPL2).