Changes in VirtualBox 4.2 beta 1:
- Improved Windows 8 support, in particular many 3D-related fixes
- GUI: VM groups
- GUI: expert mode for wizards
- GUI: allow to alter some settings during runtime
- Support for up to 36 network cards, in combination with an ICH9 chipset configuration
- Resource control: added support for limiting network IO bandwidth
- Added possibility to start VMs during system boot on Linux, OS X and Solaris
- Added experimental support for Drag'n'drop from the host to Linux guests. Support for more guests and for guest-to-host is planned.
- Support recent VIA CPUs
- Allow taking screenshots of the current VM window content
- Allow automatically sorting of the VM list
- Allow starting of headless VMs from the GUI
- GUI: network operations manager
- Improved VM context switch performance for Intel CPUs using nested paging
- Added support for FlushByASID features of AMD CPUs (Bulldozer and newer)
- Added readonly support for VHDX images, QED images and for QCOW (full support for v1 and readonly support for v2) images
- Bug fixes
Update: VirtualBox 4.2.0 RC1 is now available for download @ http://download.virtualbox.org/virtualbox/4.2.0_RC1/
sudo apt-get remove virtualbox-4.1
And then simply install the VirtualBox 4.2 beta 1 downloaded deb file.