Just a quick note : trying to open a existing VM I created with previous the previous version included in Elive ( using 5.1.38) frozed my screen. Had to go in console to close Elive.
note: due to a bug in old versions of virtualbox i think that you need first to:
sudo apt-get remove --purge virtualbox-*
and make sure that all the packages are removed and there's no modules existing in /lib/modules/ , make sure that they are unloaded or reboot your machine
Then and only then, you can install the new version (otherwise it will fail creating the module because the old one was not removed)