apt-get update and upgrade says "packages have been kept back"

Question

I ran an update and an upgrade (apt-get update and apt-get upgrade) and I get the following message:

The following packages have been kept back:
  alsa-base scratch

What do I do to get these upgrades?

Answer 1

Execute:

apt-get dist-upgrade

That will fix your problem. This is a classic apt issue. The following is taken from the man pages:

upgrade is used to install the newest versions of all packages currently installed on the system from the sources enumerated in /etc/apt/sources.list. Packages currently installed with new versions available are retrieved and upgraded; under no circumstances are currently installed packages removed, or packages not already installed retrieved and installed. New versions of currently installed packages that cannot be upgraded without changing the install status of another package will be left at their current version. An update must be performed first so that apt-get knows that new versions of packages are available.

dist-upgrade in addition to performing the function of upgrade, also intelligently handles changing dependencies with new versions of packages; apt-get has a "smart" conflict resolution system, and it will attempt to upgrade the most important packages at the expense of less important ones if necessary. So, dist-upgrade command may remove some packages. The /etc/apt/sources.list file contains a list of locations from which to retrieve desired package files. See also apt_preferences(5) for a mechanism for overriding the general settings for individual packages.  

Answer 2

Run apt-get install on the packages kept back. They require something more than a new version of that package (usually a whole other new package as a dependency). That way you'll see what each of them requires. Dist-upgrade will blindly run all of them and possibly remove anything that gets in its way.