I use a Nagios test to check whether there are any packages critical updates in some Linux boxes. The check command uses the following command to look for pending critical updates:
/usr/bin/apt-get -o 'Debug::NoLocking=true' -s -qq upgrade, that is exiting with a non-zero status. Therefore, the Nagios check is showing a warning.
If I run manually the command, I get the following message:
~# /usr/bin/apt-get -o 'Debug::NoLocking=true' -s -qq upgrade E: Packages were downgraded and -y was used without --allow-downgrades.
However, I do not remember having downgraded any package. Could you please give me a hand to get rid of this warning?