How to find which "package can be updated"?

To do a simulated update: sudo apt-get -s upgrade
To update only a single package: sudo apt-get upgrade packagename_here

You can see what updates are available by typing as sudo aptitude.

For example,

And if you don't want any package to update, then you can lock that package.

1. Open a terminal
2. Type sudo -s and hit enter

3. Enter your password for sudo

   echo libxfont1 hold | dpkg --set-selections
   

4. Replace libxfont1 with the package you want to pin
5. Now run sudo apt-get update and then sudo apt-get upgrade.

For more information, check how to pin packages.

Please do this

sudo cat /var/lib/update-notifier/updates-available

then check what packages are available for upgrade

apt list --upgradable

then just install what you need from the outcome above

sudo apt-get install PACKAGE_NAME