Rollback to previous package version after upgrade

Say that you find that an app. no longer works due to a problem with an upgraded package. As long as the previous version of the package is still in the cache, you can roll back.

The following will show all the versions of the package in the cache
Code:   

apt-cache show [package name] | fgrep Version:

   
The following will install (roll back) an older version of the package
Code:   

apt-get install [package name]=[version]

  

Another way may be possible via Synaptic.

Open Synaptic and find your package then, right click on it and there should be some menu option like "force downgrade".