This is a maintenance release. The following items were fixed and/or added:
GUI: fixed validation warning on global settings / proxy page (4.2.2 regression; bug #11089)
GUI: fixed crash with multiple guest screens on certain conditions (OS X hosts only)
VBoxBalloonCtrl: fixed command line argument handling of ballooning module
VRDP: fixed occasional crash during a video playback in the guest (bug #11082)
BIOS: fixed broken DMI information (4.2 regression)
BIOS: workaround for booting from Windows 2000 floppy disks
EFI: fixed video mode selection loss on VM reboot (bug #10983)
Parallel: fixed parallel port printing failure/ paper queue empty error (Windows hosts only)
NAT: fixed crash on alias-less DNS responses when host-resolver is used
Storage: fixed hang under rare circumstances