cannot upgrade from 16.04 to 18.04
100963
How to only perform LTS upgrades?
80233
Upgrade to 20.04 from 19.10 isn't available
42634
How do I upgrade to the development release (aka. Ubuntu+1)?
24165
Upgrade to version newer than repositories
128471
How do I update from 9.0.10 to 9.1.0?
30754
Cannot update: "No available releases found"
113056
How to upgrade from 12.04 to 12.10 using CD?
16050
Can I upgrade Xubuntu 18.04 32-bit?
59088
How to upgrade to a newer release of Ubuntu using the Live CD?
9901
How to upgrade from 18.10 to 19.10, using the command line?
55211
Problem when upgrading to Ubuntu 14.04 from Ubuntu 12.04
56150
Can't upgrade/update ubuntu 18.04 as apt/dpkg error is showing up
5316
Update from 14.04 to 16.04 failed with GPG error
76241
"no public key available" while upgrading using update-manager
75798
How to upgrade to the latest GNOME version?
12614
Upgrade problem
65099
Unable to install any updates through update manager/apt-get upgrade