Dear Maintainer,
Following updates in aptitude, I now have the following situation:
snowball:511$ dpkg -l "virtualbox*" | grep ii
ii virtualbox 6.1.26-dfsg-4 amd64 x86 virtualization solution - base binaries
ii virtualbox-dkms 6.1.28-dfsg-1+b1 amd64 x86 virtualization solution - kernel module sources for dkms
ii virtualbox-ext-pack 6.1.26-2 all extra capabilities for VirtualBox, downloader.
ii virtualbox-guest-additions-iso 6.1.22-1 all guest additions iso image for VirtualBox
ii virtualbox-qt 6.1.26-dfsg-4 amd64 x86 virtualization solution - Qt based user interface
Because virtualbox-dkms was upgraded and virtualbox was not, I am
unable to launch a VM (when I try I get an error popup). I would have
expected the varius virtualbox* packages to have been kept in sync so
this could not happen.