By default, Mojave prevents the installer for the enterprise version of iTunes 12.6.3 from working. This is a special version released AFTER v 12.7 which enabled a Mac to sync apps to iOS devices, a feature deleted in iTunes 12.7.
Today a friend at a Mac User Group meeting demonstrated how to use Pacifist app to access & install iTunes 12.6.5 (updated version of 12.6.3) onto his MacBook Pro which was running macOS 10.14.1.
Most fascinating.