Turns out, VirtualBox 6.0 was released on December 18th, 2018.
Looking at the release notes I have found the following intersting features that I've yet to try:
- Nested virtualization – avaialbe only on AMD CPUs for now – this allows you to install a hypervisor like KVM or VirtualBox inside a VirtualBox guest VM.
- Hyper-V support – apparently, VirtualBox will detect if it's running on a Windows server with Hyper-V activated, and will use Hyper-V as virtualization engine – albeit, it might run slower than native VirtualBox or Hyper-V guest VMs
- Moving stuff – both disk images and VM metadata can now be moved very easily to a new location
- Closing VMs improved – there's now an option to keep the same hardware UUID when closing a guest VM
- FUSE mount for vdisk images – on Mac OS hosts it's possible to use a vboximg-mount command for raw access to the virtual disks
I've updated my VirtualBox software page with the above notes and will be testing features and sharing.