Comment 107 for bug 1357093

No. Automatic removing is supposed to work in 16.04 and later by default. But even in 16.04 it works only, if you let unattended-upgrades install all kernel updates. I have not tested later releases, but I guess it is the same thing.

I think removing should work in 16.04 and later, if you use the configuration recommended in https://help.ubuntu.com/community/RemoveOldKernels. (i.e. setting Unattended-Upgrade::Remove-Unused-Dependencies "true";) This configuration works by 14.04, too, if you let unattended-upgrades install all kernel updates.