This is a maintenance release. The following items were fixed and/or added:
VMM: Fixed missing NULL pointer check in MMIO code
Storage: fixed having multiple NVMe controllers with ICH9 enabled (5.2.0 regression)
Network: fixed wireless detection regression when bridging to adapters with unbound IP protocols (bug #17543)
Network: fixed VERR_INTNET_FLT_IF_NOT_FOUND when bridging to some adapters on Windows hosts (possibly related bugs #15294, #15060, #13481)
Audio: Fixed interrupt storm in FreeBSD guests with HDA (bug #17219)
Keyboard: Introduced a small delay to fix old software which expects to be able to read an incoming scan code more than once (bug #17592)
Windows installer: Removed the "Ignore" action in the case the current VBox installation is still running, as the (successful) update will not work until a host reboot is performed
NAT: Handle nameserver 0.0.0.0 which is a valid setting (bug #17584)
BIOS: INT 15h/87h service must disable A20 gate when done
Linux Guest Additions: fix a hang starting KDE Plasma
