I using Ubuntu GNOME 16.04.4, and I cannot update to 18.04 from Software Updater.
I get the message
The software on this computer is up to date.
There is still no information about new release here: http://changelogs.ubuntu.com/meta-release So it will not upgrade
I was having the same problem. But then I run this command in terminal:
update-manager -cd
and I got this:
Run the above command and see if it solves your problem.
do-release-upgrade -d
to 18.04, but its not offered as already stated for stability reasons until 18.04.1 which is scheduled for 26-July -2018 (https://wiki.ubuntu.com/BionicBeaver/ReleaseSchedule) (18.04 is still marked development-release until 18.04.1) – guiverc Apr 29 '18 at 23:37