apt-get upgrade -> Do not change what is installed (only versions)
apt upgrade -> Install but not remove packages
apt-get dist-upgrade -> Install or remove packages as necessary to complete the upgrade
apt full-upgrade -> Perform the same function as apt-get dist-upgrade

sudo apt list --upgradable -> Check for upgradable packages

 apt-cache search linux-generic -> Find out the latest version of Linux kernel type on the current system
   e.g:linux-image-4*