Staring from CPBX v.5.0.60 the source of all CentOS 7, Epel and CPBX packages is set to be the repo1.xorcom.com server.
The switch from the standard CentOS 7 and Epel repositories to the new repositories is performed by the new xorcomcentos-release package that is automatically installed during the upgrade procedure to CompletePBX v.5.0.60. 
The xorcomcentos-release package replaces the standard centos-release and epel-release packages. As result of that the standard CentOS-*.repo and epel*.repo files are replaced with CompletePBX-specific files.
The cpbx.repo file is also replaced with cpbx5.repo by cpbx-upgrade package.
For your reference:
– the old set of the ‘yum’ configuration files:
   CentOS-Base.repo
   CentOS-CR.repo
   CentOS-Debuginfo.repo
   CentOS-Media.repo
   CentOS-Sources.repo
   CentOS-Vault.repo
   CentOS-fasttrack.repo
   cpbx.repo
   epel-testing.repo
   epel.repo
– the new set of the ‘yum’ configuration files after upgrade to 5.0.60:
   CentOS-Base-Xorcom.repo
   CentOS-EPEL-Xorcom.repo
   cpbx.repo.old
   cpbx5.repo
Pay attention that the original cpbx.repo is just renamed to cpbx.repo.old.
Please note that any manual changes in the *repo files won’t be overwritten during the further upgrades. Instead, the changed files will be preserved and the newer files will be installed with extension .rpmnew