Upgrading to a no longer supported version
33651
How to upgrade from Ubuntu 12.10 to 14.04
5820
How to fix the “Unable to calculate upgrade” issue from command line when upgrading from 12.04 to 14.04?
66915
How to request a package upgrade in the next Ubuntu release
53938
Can I upgrade from Windows 7 32-bit to Windows 7 64 bit without reinstalling all of my software?
46461
Unsupported software?
60659
Install newer package version from trusty-backports
43272
Can't update iPhone to a specific version : "iphone could not be restored device isn't eligible for the requested build"
63176
How can I update to Ubuntu 21.04?
23302
How do I install/upgrade r-base to the latest version?
48809
"The upgrade has aborted" error, how to proceed?
129223
Ubuntu upgrade from 17.04 to 18.04
86777
Distribution upgrade problem "No new release found"
2136
How to roll back Ubuntu to a previous version?
23096
How to remove obsolete packages after failed release upgrade via do-release-upgrade on Ubuntu?
75621
Store won't open after upgrade
11166
"Require Installation Of Untrusted Packages" while upgrading with the update manager
116445
"Can't check signature: public key not found" while upgrading, why?