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

- VMM: several fixes
- GUI: fixed screenshot if the VM is started in separate mode
- GUI: fixed issue with double-click/opening registered file types (.vbox and .vbox-extpack) on Mac OS X (bug #15648)
- GUI: fixed a bug which made it impossible close some error/warning messages using the close button
- GUI: weakened the control over the VM window behavior allowing to resize it across multiple screens and to use in Snap Assist techniques
- GUI: jump to the second tab of the session information window (5.1.0 regression)
- GUI: fix for Alt-Tab
- Storage: fixed creating fixed size VHD images (bug #15601)
- Storage: fixed a hang during power off if the VM was suspended before and a NVMe controller is configured
- USB: fixed a crash under certain conditions
- Audio: make AC'97 volume control work again (5.1.0 regression; bug #15598)
- Audio: fixed rare VM hangs when using AC'97 emulation
- Audio: SB16 fixes
- EFI: fixed access to devices attached to SATA port 2 and higher (bug #15607)
- OVA: fix for checking certain signatures
- OVA: fixed MAC address generation for appliances created by VirtualBox (5.1.0 regression; bug #15623)
- API: fixed audio settings handling for older config files (bug #15626)
- API: fixed truncation of USB product/vendor IDs on Linux hosts (5.1.0 regression; bug #15644)
- API: fixed VRDP with authentication (bug #15653)
- API: don't crash if there is no graphics controller configured (bug #15628)
- Linux hosts: fixed EL5 builds (bug #15634)
- non-Windows hosts: fixed a crash during shutdown under rare circumstances (bug #15568)
- Linux Additions: fixed SELinux issue which prevented certain Linux guests to work in 3D mode (bug #15574)
- User Manual: updates