This version is a major update. The following major new features were added:

• OVF (Open Virtualization Format) appliance import and export (see chapter 3.8, Importing and exporting virtual machines, User Manual page 55)
• Host-only networking mode (see chapter 6.7, Host-only networking, User Manual page 88)
• Hypervisor optimizations with signi?cant performance gains for high context switching rates
• Raised the memory limit for VMs on 64-bit hosts to 16GB
• VT-x/AMD-V are enabled by default for newly created virtual machines
• USB (OHCI & EHCI) is enabled by default for newly created virtual machines (Qt GUI only)
• Experimental USB support for OpenSolaris hosts
• Shared folders for Solaris and OpenSolaris guests
• OpenGL 3D acceleration for Linux and Solaris guests (see chapter 4.8, Hardware 3D acceleration (OpenGL), User Manual page 70)
• Added C API in addition to C++, Java, Python and Web Services

In addition, the following items were ?xed and/or added:

• VMM: FreeBSD guest related ?x for V86 ?ags (bug #2342)
• VMM: ?xed guru meditation when booting an AsteriskNow Linux VM (bug #2342)
• VMM: ?xed PGMPOOLKIND_FREE guru meditation (bugs #3356, #3431)
• VMM: ?xed Windows XP boot hang (guest PAE + nested paging only)
• VMM: allow mixing of VT-x/AMD-V and software virtualization
• VMM: ?xed extremely slow safe mode booting in e.g. Windows 2008 (VT-x/AMD-V only)
• VMM: signi?cant speedup of certain GRUB boot loaders (e.g. Solaris) (VT-x/AMD-V only)
• VMM: real-mode IOPL ?x for DOS guests (VT-x only)
• VMM: ?xed VT-x detection with certain BIOSes that enable VT-x, but don’t set the lock bit in MSR_IA32_FEATURE_CONTROL
• VMM: ?xed hibernation issues on Windows XP hosts (VT-x only; bug #1794)
• VMM: properly emulate RDMSR from the TSC MSR, should ?x some NetBSD guests
• VMM: emulate RDPMC; ?xes Windows guests crashes when using the Kaspersky virus scanner (bug #1778)
• NAT: ?xed truncated downloads (FTP) (bug #3257)
• NAT: blocked UDP packets caused a crash (bug #3426)
• NAT: allow to con?gure the next server and the boot ?le via VBoxManage (bug #2759)
• IDE: ?xed hard disk upgrade from XML-1.2 settings (bug #1518)
• Hard disk: support more VMDK ?le variants (including ?xed-size ESX server images)
• Hard disks: refuse to start the VM if a disk image is not writable
• USB: further reduced host CPU utilization for OHCI and EHCI; the “VBoxInternal/Devices/usb-ohci/0/Con?g/FrameRate” CFG key is no longer necessary and no longer supported
• USB: ?xed BSOD on the host with certain USB devices (Windows hosts only; bug #1654)
• E1000: properly handle cable disconnects (bug #3421)
• VRDP: ?xed hangs when VRDP server is enabled or disabled in runtime
• Shared folders: respect umask settings on Linux, OSX and Solaris hosts when creating ?les
• X11 guests: prevented setting the locale in vboxmouse, as this caused problems with Turkish locales (bug #3563)
• X11 guests: show the guest mouse pointer at the right position if the virtual desktop is larger than the guest resolution (bug #2306)
• Linux additions: ?xed typo when detecting Xorg 1.6 (bug #3555)
• Solaris guests: added xpg4/xcu4 dependency to the guest additions installer (bug #3524)
• Windows guests: bind the VBoxMouse.sys ?lter driver to the correct guest pointing device (bug #1324)
• Windows hosts: ?xed BSOD when starting a VM with enabled host interface (bug #3414)
• Linux hosts: do proper reference counting to prevent unloading the vboxnet?t module as long as this code is in use (bug #3104)
• Linux hosts: do not leave zombies of VBoxSysInfo.sh (bug #3586)
• Linux installers: ?xes for Slackware, Arch Linux and Linux from Scratch systems
• Windows installers: combined installer executable which contains both (32- and 64-bit) architectures.
• VBoxManage: less cryptic command-line error messages
• VBoxManage list vms commands now default to compact format
• VBoxManage controlvm dvdattach did not work if the image was attached before
• VBoxManage: allow creation of all supported disk image variants
• VBoxManage showvminfo : don’t spam the release log if the additions don’t support statistics information (bug #3457)
• VBoxManage: big command line processing cleanup, the legacy single-dash options are deprecated and will be removed in the next major release, so switch to the new options now
• Hard disks: improved immutable disk support to auto-reset diff ?le at VM startup (related to bug #2772)
• GUI: enable the audio adapter by default for new VMs
• GUI: warn if VT-x/AMD-V is not operational when starting a 64-bit guest
• GUI: deactivate 64-bit guest support when the host CPU does not support VT-x/AMD-V
• GUI: removed ?oppy icon from the status bar
• GUI: show build revision in about dialog
• GUI: ?xed sticky status bar text
• GUI: improved error dialogs
• GUI: fail with an appropriate error message when trying to boot a read-only disk image (bug #1745)
• GUI/Mac OS X: ?xed disabled close button
• GUI/Windows: re-enabled support for copy and paste (Windows hosts 2.0 regression; bug #2065)
• 3D support: added OpenGL select/feedback support (bug #2920)
• 3D support: close OpenGL subsystem for terminated guest applications (bug #3243)
• 3D support: ?xed VM hangs when starting guests with 3D acceleration enabled (bug #3437)
• PXE: ?xed boot hangs when hardware virtualization is used (bug #2536)
• LsiLogic: ?xed problems with Solaris guests
• Main API: close machine settings XML ?le when unregistering machine (bug #3548)