linux – CentOS yum update: packages skipped because of dependency problems?

I’m in the process of updating a server running CentOS that hasn’t been updated in years. There were over 400 packages to update, but 6 packages were skipped due to dependency problems. After updating all the other packages, I cleaned the yum cache and these 6 packages are still listed.

What does this mean and how do I resolve this? Will ignoring these skipped packages cause any problems for the system?

I should add that I’m doing this update as one of my first projects at my first IT job. A lot of this is new to me.