Unable to upgrade from 12.04 to 14.04
4305
How do I fix a "Problem with MergeList" or "status file could not be parsed" error when trying to do an update?
67481
How to revert a do-release-upgrade?
113942
Is it possible to install Python 3.x in 14.04 LTS, or upgrade from Python 2.7.6 to 2.7.8?
48809
"The upgrade has aborted" error, how to proceed?
118307
Why does upgrade from 12.04 to 12.10 using a CD/DVD still require download?
123413
Will apt-get dist-upgrade upgrade my system to a newer version?
9901
How to upgrade from 18.10 to 19.10, using the command line?
98844
upgrade 14.04 with errors and shows red sign on top
56150
Can't upgrade/update ubuntu 18.04 as apt/dpkg error is showing up
11579
Broken dependencies after upgrade
64509
Can't update from official repositories [Error 409]
135383
Unable to update my system Ubuntu13.04: Getting message - requires installation of untrusted packages
115421
Ubuntu 13.10 to 14.04 Lts does not upgrade, keeps showing error
128471
How do I update from 9.0.10 to 9.1.0?
12534
14.04 --> 16.04 failed; apt (>= 1.0.1ubuntu2.13)' is not installed
24603
apt-get upgrade gives "403 forbidden" error
77705
Unable to upgrade in ubuntu