How to get Linux Update info from client

I've got the 'xymon-client' installed on many machines and was wondering if the client gathers any info regarding Security and Package updates that can be updated?  I've searched the 'clientlog' and there's no mention of Updates anywhere.  Does anyone have a way to view available updates from linux clients?

See https://wiki.xymonton.org/ for a xymon client script to do just that for Red Hat (yum), and one for raspbian (apt). Depending on the *nix versions you are using, you can deploy a possible adapted version of those scripts.

Regards,
  Wim Nelis.