Downgrading to iTunes 12.6 on High Sierra

I work for a school district who uses the Apple Configurator 2 + iTunes to locally install iPad apps en mass. With the update to 12.7, I have lost the ability to install apps via the Apple Configurator 2 application.

From a clean install of High Sierra, how can I downgrade to iTunes 12.6 to continue installing iPad apps from iTunes through the Apple Configurator 2 software onto iPads?

Thanks,

Marcus