Sometimes when using the apt-get command to upgrade, you may have packages that are being kept back.
Something similar to what is shown below
$apt-get upgrade Reading package lists... Done Building dependency tree Reading state information... Done The following packages have been kept back: libgssapi-krb5-2 libgssrpc4 libk5crypto3 libkadm5srv6 libkrb5-3 libkrb5-dev libkrb5support0 0 upgraded, 0 newly installed, 0 to remove and 7 not upgraded.
In the screen example above, there are 7 packages being kept back.
The reason why they are not being upgraded by apt-get upgrade is because those packages now have dependencies on packages which are currently not installed on the system.
apt-get upgrade will only install newer versions of packages which are already installed.
To fix this problem, you should use the apt-get dist-upgrade
This will automatically install packages which are needed in order to perform the upgrades.
hope this helps