VirtualBox 5.2.40 (released April 14 2020)
https://www.virtualbox.org/wiki/Changelog-5.2#v40

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

VBoxManage: Multiple fixes for guestcontrol command
USB: Multiple enhancements improving prformance and stability
Graphics: Enhancements in 2D and 3D acceleration and rendering
API: Fix exception handling bug in Python bindings
Linux: Support Linux kernel 5.6 (bug #19312)


VirtualBox 6.0.20 (released April 14 2020)
https://www.virtualbox.org/wiki/Changelog-6.0#v20

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

USB: Multiple enhancements improving prformance and stability
VBoxManage: Multiple fixes for guestcontrol command
Graphics: Enhancements in 2D and 3D acceleration and rendering
API: Fix for exception handling bug in Python bindings
Linux host and guest: Support Linux kernel 5.6 (bug #19312)


VirtualBox 6.1.6 (released April 14 2020)
https://www.virtualbox.org/wiki/Changelog-6.1#v6

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

GUI: Multiple enhancements including visual elements updates
Graphics: Fixed monitor resizing and multi-monitor handling bugs on X11 guests with VMSVGA graphics adapter
Graphics: Enhancements in 2D and 3D acceleration and rendering
USB: Multiple enhancements improving prformance and stability
Serial port: Improve error handling and fix hang when host port disappears
VBoxManage: Multiple fixes for guestcontrol operations
API: Fix for exception handling bug in Python bindings
Shared clipboard: Multiple fixes including possible crash and HTML data support
Linux host and guest: Support Linux kernel 5.6 (bug #19312)