Comment 2 for bug 1052629

Here's an extract from VarLogDistupgradeApttermlog.gz :

+++
Setting up lcdproc (0.5.5-2) ...

Configuration file `/etc/LCDd.conf'
 ==> Modified (by you or by a script) since installation.
 ==> Package distributor has shipped an updated version.
   What would you like to do about it ? Your options are:
    Y or I : install the package maintainer's version
    N or O : keep your currently-installed version
      D : show the differences between the versions
      Z : start a shell to examine the situation
 The default action is to keep your current version.
*** LCDd.conf (Y/I/N/O/D/Z) [default=N] ? dpkg: error processing lcdproc (--configure):
 EOF on stdin at conffile prompt
dpkg: dependency problems prevent configuration of lcdproc-extra-drivers:
 lcdproc-extra-drivers depends on lcdproc (= 0.5.5-2); however:
  Package lcdproc is not configured yet.
dpkg: error processing lcdproc-extra-drivers (--configure):
 dependency problems - leaving unconfigured
+++

Looks like the question asked by debconf was not answered. This version of lcdproc cannot be upgraded wihtout answering this question.

Starting from lcdproc 0.5.6, unattended upgrade are working, thanks to the automatic configuration upgrade performed by Config::Model