Pretty sure CentOS 7 is a InterWorx 5.1 update. Might be showing up because of that, but I wouldn’t try installing anything but the 5.1 beta on CentOS 7.
It’s not fully supported yet. You need to use the 5.1 Beta on Centos 7 to use it, and there’s no apache modules for it yet, so best to wait. We’re going to move to it as-well :).