The recommended VirtualBox version for Windows is VirtualBox for Windows Hosts 6.1.14
The recommended VirtualBox version for macOS is VirtualBox for macOS Hosts 6.1.16
VirtualBox package from Canonical (currently 6.1.26-dfsg-3~ubuntu1.20.04.1) has been fully tested and is recommended with Ubuntu 20.04LTS. We cannot guarantee the result with other Ubuntu releases.
Debian 9 "Stretch"
VirtualBox from the Debian 9 repository has been fully tested and is recommended. We cannot guarantee that it will work with Debian 10 or 11, since these releases have not been tested.
VirtualBox 6.1.26 from the RPM repository provided by VirtualBox development have been tested on Fedora Workstation 30. It should also work with Fedora Workstation 34, but this has not been tested.
Other Linux distributions have not been tested and we cannot guarantee the result, nor provide technical support for them. If you choose to run Genymotion Desktop on an unsupported Linux distribution, you do it at your own risks.