If you want to update your os then this is it...
Quotesudo apt-get update && time sudo apt-get dist-upgrade
upgrade
upgrade is used to install the newest versions of all packages
currently installed on the system from the sources enumerated in
/etc/apt/sources.list. Packages currently installed with new
versions available are retrieved and upgraded; under no
circumstances are currently installed packages removed, or packages
not already installed retrieved and installed. New versions of
currently installed packages that cannot be upgraded without
changing the install status of another package will be left at
their current version. An update must be performed first so that
apt-get knows that new versions of packages are available.
dist-upgrade
dist-upgrade in addition to performing the function of upgrade,
also intelligently handles changing dependencies with new versions
of packages; apt-get has a "smart" conflict resolution system, and
it will attempt to upgrade the most important packages at the
expense of less important ones if necessary. So, dist-upgrade
command may remove some packages. The /etc/apt/sources.list file
contains a list of locations from which to retrieve desired package
files. See also apt_preferences(5) for a mechanism for overriding
the general settings for individual packages.
apt-get upgrade will not change what is installed (only versions),
apt-get dist-upgrade will install or remove packages as necessary to complete the upgrade,
apt upgrade will automatically install but not remove packages.
apt full-upgrade performs the same function as apt-get dist-upgrade.
The upgrade option only installs new version of the packages that are already installed on the system (and yes, kernel updates belong to them).
However, sometimes the updates change dependencies: for example, a new version of a package will no longer depend on a library that you have installed, or will require installation of additional libraries. The upgrade option will never remove installed packages that you no longer actually need.
However, the dist-upgrade option can "intelligently" handle changes in the dependencies system. This includes removing packages that are no longer necessary or resolve conflicts between packages that arose because of changes in the dependencies.