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

• VM export to Oracle Cloud (OPC)
• Unattended guest installation (bug #5810; see the manual for more information)
• Overhauled VM selector GUI (improved tools VM / global tools handling, new icons)
• Added experimental audio support for video recording

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

• VMM: fixed reason for recent Linux kernels on also recent CPU models warning about "XSAVE consistency problem"
• GUI: Virtual Media Manager rework allowing to manage media attributes, like size, location, type and description
• GUI: Host-only Network Manager implemented to simplify managing corresponding networks and their attributes
• GUI: Snapshot Pane rework allowing to manage snapshot attributes, like name and description; reworked snapshot details which looks more clear, corresponds to VM Details pane and reflects current VM state difference according to last snapshot taken
• GUI: Audio settings extended with possibility to enable/disable audio input/output; corresponding changed were done to Audio and Video Capture settings pages; VM Devices menu and status-bar extended with corresponding actions and indicator as well
• GUI: improvements with accessibility support
• GUI: Fixed double mouse cursor when using mouse integration without Guest Additions, actually a Qt 5.6 bug fixed with QT 5.6.3 (Mac OS X hosts only; bug #15610)
• Audio: implemented (optional) device enumeration support for audio backends
• Audio: implemented support for host device callbacks (e.g. when adding or removing an audio device)
• Audio: HDA emulation now uses asynchronous data processing in separate threads
• Audio: implemented ability to enable or disable audio input / output on-the-fly
• Storage: implemented support for CUE/BIN images as CD/DVD media including multiple tracks
• Storage: implemented support for the controller memory buffer feature for NVMe
• Storage: first milestone of the I/O stack redesign landed
• E1000: Fix for Windows XP freeze when booting with unplugged cable
• NAT network: do not skip some port forwarding setup when multiple VMs are active (Windows hosts only; bug #17041)
• Serial: fixed extremely rare misbehavior on VM poweroff
• EFI: better video mode handling, supporting custom video modes and easier configuration (bug #6783)
• BIOS: properly report floppy logical sectors per track for unusual formats
• BIOS: update ATA disk parameter table vectors only if there is actually a corresponding ATA disk attached
• PXE: speed up booting by better handling pending packets when the link is not up yet
• VBoxManage: handle CPUID sub-leaf overrides better
• Windows Additions: fix several 3D related crashes
• Solaris hosts: allow increasing MTU size for host-only adapter to 9706 bytes to support jumbo frames
• Linux Additions: on systems using systemd, make sure that only the Guest Additions timesync service is active
• many unlisted fixes and improvements