I keep getting numerous notifications throughout the day that there are updates. However, running the updater shows a different story. Running sudo apt update && sudo apt upgrade -y says all is up to date.
Which should I trust?
SnapOverflow
It is a common scenario. To make things easier for newbies Ubuntu by default considers that all operations are done in Graphical User Interface and not Command Line Interface. However if someone still uses terminal to manually update then the notification comes without any real update present. Just click OK to update and you will most probably see that the pop up menu straightaway says that your computer is up to date instead of showing the update progress bar.