Ubuntu Software updates error on 12.04 LTS version
135383
Unable to update my system Ubuntu13.04: Getting message - requires installation of untrusted packages
105335
How do I upgrade my Ubuntu server from one LTS version to another? Is this safe?
5820
How to fix the “Unable to calculate upgrade” issue from command line when upgrading from 12.04 to 14.04?
150033
E: Sub-process /usr/bin/dpkg returned an error code (1) for almost all updates
87236
How to upgrade Ubuntu 12.04 to 13.10?
120161
Ubuntu 19.04 problems install upgrades
2670
Why is "No new release found" when upgrading from a LTS to the next?
44209
Problem with update-manager: No module named 'apt_pkg' in Ubuntu 13.10, having installed Python 3.4 on /usr/local/lib
23511
Installing R on Ubuntu - getting updates to work
249
How do I fix this "E: Type '*' is not known on line * in source list ..." update error?
51350
While updating the ubuntu 16.04 does not have a Release file Error
119943
Where can I find a repository for older unsupported releases?
69200
How do I reinstall Ubuntu Software in Ubuntu 20.04 LTS version?
74990
Error while trying to upgrade from Ubuntu 18.04 to 18.10: "Please install all available updates for your release before upgrading."
1632
How do I fix a "Failed to download package files" error?
12614
Upgrade problem
107792
Update information outdated, "Failed to fetch cdrom"