CentOS 7 will receive patches for nearly 4 more years.I think it's time to migrate to latest centos 8 just to be sure but hoping there will be more patches in 7.
What it won't do is provide patches for outdated point releases. That's always been the way it works - only the current point release gets patches and people running older ones (i.e anyone on 7.7 or less currently) will be told to update to $latest.