This is a maintenance release. The following items were fixed and/or added:

- User interface: fixed a segmentation fault when accessing the interface through VNC (bug #16348)
- User interface: X11: handle repeating keys on the host system correctly (bug #1296, previously fixed, 5.1.0 regression)
- VMM: Fixed emulation of the undocumented SALC instruction
- VMM: Fixed emulation of so-called "huge unreal mode" (bug #17744); this in practice only affected Intel CPUs with VT-x without unrestricted execution.
- Keyboard: The PS/2 keyboard emulation has been corrected to not queue partial scan code sequences (bug #17709); this problem was likely only visible on Linux hosts due to losing the fix for bug #1296
- Storage: Fixed CUE file support to correct REM keyword parsing (bug #17783)
- USB: Fixed a problem where the emulated xHCI device under very rare circumstances failed to report an empty isochronous transfer ring error, causing the transfers on the corresponding endpoint to stop.
- Audio: fixed Linux kernel log flooding (bug #17759)
- Apple hosts: make kernel driver load with Mac OS Mojave pre-release (bug #17805).
- Linux guests: made vboxvideo driver build with kernel 4.17 (bug #17801) and with pre-3.14 and EL 7.1 kernels (bug #17771)