With iOS 11.3, the concept of “managed documents” has been extended to “managed contacts”, meaning that all address book entries that come from Relution including managed mail accounts will be internally separated from your iCloud contacts. By opting out of the option “Allow open managed documents in unmanaged apps” in the iOS Restrictions in your Relution policy, unmanaged apps (i.e. those that have not been installed via Relution) can no longer access these contacts. This finally solves the problem that WhatsApp and other private apps will grab all your business contacts without asking for permission. Also, in settings–>contacts on your iOS device, you can define whether new contacts will be stored in your private (iCloud) or your business address book.