I upgraded via command line from Kubuntu 14.04.3 amd64 to 15.04 by the do-release-upgrade command.
I don't know why do-release-upgrade skipped 14.10. I expected to have to go through it to get to the latest.
There were some errors during upgrade in about six packages, but they looked non-critical and it said the upgrade was complete so I tried to reboot. It would not shutdown because /bin/shutdown was missing. So I hard powered off.
Boot hangs on "/proc/self/fd/9: 31: /proc/self/fd/9: telinit: not found"
Tried booting into recovery, got kernel panic: init not found.
Same result with all previous kernels installed.
There are more grub options now. There are three options for each kernel: normal, upstart, and recovery. I have tried them all.