Re: Upgrade, but not right now?
This is normal for Ubuntu. Its been like this since at least 10.02.
For the first few months, you need to install from scratch if you want the new release. I guess this is because when installing from scratch, it is easier to know the eventual state of the system, whereas upgrading starts from an unknown state, so more testing is required to make sure that they get all of the dependencies right.
This is doubly so from a 2 year old LTS release rather than the previous non-LTS release.
I'm wondering what my best upgrade path is form 14.04 (I am still not convinced by systemd, and I'm actually using Gnome Fallback). I think I will have to go trough 16.04 before 18.04. Still, at least a year of support left for 14.04.