Ever wondered why apt keeps some packages back when doing an
apt-get update && apt-get upgrade?
apt-get upgrade Reading package lists... Done Building dependency tree... Done The following packages have been kept back: cpp gcc libcurl3 ssh tasksel x-window-system-core xbase-clients xlibmesa-gl xutils 0 upgraded, 0 newly installed, 0 to remove and 9 not upgraded.
The message actually means that there is a new package version available but for some reason it can not be installed. Maybe the package has broken or new dependencies. If you want further information about a specific packages this can be done by setting a special options like shown below.
apt-get -s -o Debug::pkgProblemResolver=yes install xutils > /dev/null Starting Starting 2 Package xutils has broken dep on xbase-clients Considering xbase-clients 4 as a solution to xutils 10013 Added xbase-clients to the remove list Fixing xutils via remove of xbase-clients Package x-window-system-core has broken dep on xbase-clients Considering xbase-clients 4 as a solution to x-window-system-core 0 Re-Instated libglu1-xorg Re-Instated libdmx1 Re-Instated libxkbfile1 Re-Instated libxkbui1 Re-Instated libxss1 Re-Instated libxxf86dga1 Re-Instated libxxf86misc1 Re-Instated libxxf86vm1 Re-Instated xbase-clients Re-Instated x-window-system-core Package xlibmesa-glu has broken dep on libglu1 Considering libglu1-xorg 0 as a solution to xlibmesa-glu 15 Added libglu1-xorg to the remove list Considering libglu1-mesa 0 as a solution to xlibmesa-glu 15 Fixing xlibmesa-glu via keep of libglu1-xorg Package x-window-system-core has broken dep on libglu1-xorg Considering libglu1-xorg 0 as a solution to x-window-system-core 0 Holding Back x-window-system-core rather than change libglu1-xorg Done
Usually the problem can be resolved by explicitly installing the desired held back packages. For further information check out the APT-Howto.