New features since 3.0:
* Management Stack based of Salt Stack in dom0
* Out of the box Whonix setup
* UEFI support
* LIVE edition (still alpha, not part of R3.1-rc1)
* Updated GPU drivers in dom0
* Colorful window application icons (instead of just colorful lock icon)
* PV Grub support (documentation)
* Out of the box USB VM setup, including handling USB mouse
* Xen upgraded to 4.6, for better hardware support (especially Skylake platform)
* Improve updates proxy flexibility – especially repositories served over HTTPS
https://www.qubes-os.org/news/2015/12/08/qubes-OS-3-1-rc1-has-been-released/
https://www.qubes-os.org/doc/releases/3.1/release-notes/
Firmware Security 