Package: grass Version: 6.0.0-1 Severity: important $ apt-cache show grass Package: grass Version: 6.0.0-1 Depends: ... xterm, libgrass If you don't put a version number on the libgrass dependency, doesn't that mean "apt-get install grass" won't get fresh libgrass if old libgrass is already installed !!! apt-get upgrade will but apt-get install grass won't!