I think the problem was that I was using Wayland instead of Xorg. It seems that the update-manager is supposed to tell me about the availability of an upgrade, but it didn't do that. I tried this command but got only errors: sudo update-manager -d To fix that, I logged out, but when I logged back in, I clicked the wheel icon and chose Ubuntu Xorg. Then I ran the update-manager command again and it worked, asking me if I wanted to upgrade. I wonder how many people will get stuck forever with 17.10 because it will never tell them about the upgrade. Mike