I performed another upgrade without ubuntu-release-upgrader (edit sources, apt-get update, apt-get dist-upgrade) and the modules were not built for the new kernel.
bdmurray@clean-yakkety-amd64:~$ dkms status
virtualbox, 5.1.18, 4.8.0-26-generic, x86_64: installed
Reinstalling linux-headers-4.10.0-19-generic again resolved the issue.
I performed another upgrade without ubuntu- release- upgrader (edit sources, apt-get update, apt-get dist-upgrade) and the modules were not built for the new kernel.
bdmurray@ clean-yakkety- amd64:~ $ dkms status
virtualbox, 5.1.18, 4.8.0-26-generic, x86_64: installed
Reinstalling linux-headers- 4.10.0- 19-generic again resolved the issue.