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
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

$apt-get dist-upgrade

This will automatically install packages which are needed in order to perform the upgrades.

hope this helps

Edwin is the founder and editor of Little Handy Tips and Wollongong Fitness. He is also the developer for the Google Custom Search WordPress plugin and Custom About Author WordPress plugin. Find out more about him here.