# New features were added
* GUI: keep the aspect ratio in scale mode (Windows and OSX hosts only)
* Experimental support for PCI passthrough for Linux hosts, see Section 9.6, “PCI passthrough”
* Networking: new network attachment mode "Generic Driver", which offers an open plugin architecture for arbitrary and separately distributable virtual network implementations
* Experimental support for SATA hotplug added. Currently only supported for hard disks and only with VBoxManage.

# The following items were fixed and/or added:

* GUI: decrease time before showing the VM configuration dialog
* Settings: provide better diagnostics if a single medium is used twice in a VM config
* Settings: provide better diagnostics for errors in medium create/merge/clone operations, and fix memory leaks in error cases
* Storage: ATA/SATA drives can be marked as non-rotational, i.e. the guest OS will detect them as a SSD if supported, which can improve performance
* Storage: virtual CD/DVD images will be detached if the guest ejects the medium, unless the drive is marked to handle ejects only on a temporary basis
* Storage: the medium UUID can be changed again when attaching a medium for the first time, which allows using images which are exact duplicates including the UUID
* Storage: fixed possible data corruption under certain circumstances with VHD and Parallels images
* Storage: fixed unnecessary expansion when cloning differential images in VDI format
* Storage: fixed detection code to handle empty files for VDI and VMDK format
* Floppy: make it possible to unmount a host floppy disk
* Networking: workaround for a bug in wireshark when operating directly on a capture file created by VirtualBox
* Webservice: fixed timeout handling with HTTP 1.1 keepalive, and be more robust when connections fail
* VBoxSVC: fixed regression when several clients trigger autostart simultaneously
* Main: fixed incorrect handling of the medium location for media which are not file based (e.g. iSCSI), which resulted in confusing location values in many places
* JAX-WS client bindings: fixed resource leak
* Sources: fixed USB 2.0 support using extension packs for non-official builds
* Windows hosts (64-bit only): enabled removing of all mediums when removing a VM
* Windows hosts (64-bit only): enabled live snapshot deletion
* Solaris Additions: fixed automounting of shared folders