You can entirely disable iMessage (and FaceTime, and Siri, etc) via provisioning profiles on a managed device. Use Apple Configurator 2 to do so. (A very impo

You can entirely disable iMessage (and FaceTime, and Siri, etc) via provisioning profiles on a managed device. Use Apple Configurator 2 to do so. (A very important privacy setting with no corresponding toggle in the UI that can only be set via a configuration profile is the option to not auto sync your list of recently emailed people to iCloud (“Disable recents syncing”). This leaks your email contact history and social graph to Apple if you have iCloud turned on, even if you aren’t using an Apple email account and aren’t using iCloud Contacts. AFAIK there’s no way to disable it other than via configuration profile.) This is what I do.