Comment 9 for bug 1681566

I just did an upgrade from Y to Z with the virtualbox packages installed and observed the same behavior as with the nvidia DKMS modules.

Setting up virtualbox-dkms (5.1.18-dfsg-1build1) ...^M
Loading new virtualbox-5.1.18 DKMS files...^M
Building for 4.8.0-46-generic^M
Building initial module for 4.8.0-46-generic^M
Done.^M
^M
vboxdrv:^M
Running module version sanity check.^M
 - Original module^M
   - No original module exists within this kernel^M
 - Installation^M
   - Installing to /lib/modules/4.8.0-46-generic/updates/dkms/^M
^M
vboxnetadp.ko:^M
Running module version sanity check.^M
 - Original module^M
   - No original module exists within this kernel^M
 - Installation^M
   - Installing to /lib/modules/4.8.0-46-generic/updates/dkms/^M
^M
vboxnetflt.ko:^M
Running module version sanity check.^M
 - Original module^M
   - No original module exists within this kernel^M
 - Installation^M
   - Installing to /lib/modules/4.8.0-46-generic/updates/dkms/^M
^M
vboxpci.ko:^M
Running module version sanity check.^M
 - Original module^M
   - No original module exists within this kernel^M
 - Installation^M
   - Installing to /lib/modules/4.8.0-46-generic/updates/dkms/^M
^M
depmod...^M
^M
DKMS: install completed.^M

The modules were only built for the 4.8 kernel.

bdmurray@clean-yakkety-amd64:~$ ls /lib/modules/4.10.0-19-generic/
build kernel modules.alias.bin modules.builtin.bin modules.dep.bin modules.order modules.symbols vdso
initrd modules.alias modules.builtin modules.dep modules.devname modules.softdep modules.symbols.bin
bdmurray@clean-yakkety-amd64:~$ ls /lib/modules/4.8.0-46-generic/updates/dkms/
vboxdrv.ko vboxnetadp.ko vboxnetflt.ko vboxpci.ko