When upgrading packages on Ubuntu using the apt-get upgrade command you may notice that some packages are not upgraded. Ubuntu will not upgrade packages that could have a major impact to service on the server such as the kernel, kernel headers, MySQL packages, and various others. The packages are held back by aptitude as a safeguard to keep people from upgrading packages that might keep the server from rebooting or that might corrupt something like a database. Below we show the error in more detail and explain the command that can be run to upgrade the packages that are being held back.
While doing some testing this evening on Backtrack Linux 5 R3 I had issues with apt or aptitude complaining about some dependencies for packages I had compiled from source. One of the packages I first ran into issues with was bluez which is installed by default on Backtrack. I wanted to apply a patch to the source code and then reinstall bluez which I was able to accomplish. The issue started after that when apt started complaining that bluez was not installed any longer. Below I describe how I modified the apt dependencies tracker file which fixed my unmet dependencies errors.