You can upgrade Asterisk through the CLI after install. We don’t update the installer for every Asterisk release, that would get out of control
yum install sangoma-devel
yumdownloader --source <rpm>
As you’ll note here on every RPM it’s marked with shmz6.5. Which is the old distro. Not the 7 distro. If you use any of these SRPMs on the new distro you will break the system.