dave simmons
Joomla & Drupal are popular. The choice will depend on features you require. They will both do standard functions OK, both are very full featured and may be overkill for a small website.
Also look at basic website functionality of Wordpress.
Most of these you will have to upgrade manually from the support website, follow their instructions, unless they have built in upgrade functions, I think Wordpress does.
Unless a contributor releases contrib upgrades, then they will not be in smecontribs repo, and as far as I know there are no upgrade rpms in smecontribs (for CMs's), just the original "install first time" contrib, which is usually an older version, some are much older. It may be just as easy to install from tar.gz files and set them up manually to the latest version.
I suggest you lock into using only one CMS (eg Joomla is my personal choice), others opinions may vary, and use that for all your needs, that way you can apply the knowledge of how to use & upgrade that application and spread it across a few users. You will need to be on sme8 for compatibility with these nowadays, but I see a pre-release 8.0 final iso has been released for testing, so no problems there.
It is important to subscribe to email notification lists for these packages so you are aware of security issues immediately etc, and follow through and update your server.
An alternative approach is to have Joomla or whatever hosted externally, and there is less critical need to do updates, and the rest of your server is not at risk of cross hacking etc. I've seen Joomla hosting for $9.95 per month.