One of my baremetal installs still says beta

Release
System version
NethServer release 7.5.1804 (beta)
Kernel release
3.10.0-862.6.3.el7.x86_64

Perhaps this helps you too:

echo > /etc/yum/vars/nsrelease
yum clean all && yum update

Could you tell us a little bit more. How did you try to update, softwarecenter or console? Are there any errors?