As explained here How can I fix Networking, Wi-Fi and Ethernet, not being available after update? there is a regression bug that will cause some systems to lose network entirely.
Lewis' excellent answer solves the issue, but after applying it I am immediately requested by the system to upgrade the downgraded libraries:
As far as I can tell, I have the Poposed repository[*] deselected:
Lewis says to "so comment out the lines in
/etc/apt/sources.list", but I'm not sure which lines he is referring to.
[*]: I actually have all of the repositories in the Updates tab deselected. Is this how they should show?