Ubuntu end of life (EOL) fix
Package updates will no longer work after the [Ubuntu EOL date] for your version. You will see error messages like this:
Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. Since you only requested a single operation it is extremely likely that the package is simply not installable and a bug report against that package should be filed. The following information may help to resolve the situation: The following packages have unmet dependencies <packages> E: Broken packages
An update to sources.list is required as follows:
Now package updates should work properly.