[CentOS] Not getting updates?

I installed CentOS 7 late last year to use as my Nagios/Cacti Monitoring server. Clean install, nothing real complicated just the server version with no GUI, just command line/SSH.

I have noticed over the last 3 months that I've not had ANY updates when I run 'yum update'. I have run 'yum clean all' to see if that might be a problem, and I've made sure the updates repo is enabled (it is), but I'm getting no CentOS updates.

Did something change that I'm not aware of? I'm even clueless how to being debugging this. I'm no noob to RPM based systems as I run Fedora pretty much everywhere else.

Ideas?