iOS Local Push Notification using Cellular Data

We are working on a project that's required to be in a fully isolated network using VPN. We would like to find if there's any way to sending and receiving Push notifications without using APNs servers. We found a topic in Apple documentation "Local Push Connectivity" but it requires the iOS device to be using a specific SSID that requires WiFi to work as mentioned in Apple documentation: "When a user’s iOS device joins a Wi-Fi network that has an SSID matching a configured SSID in your NEAppPushManager instance, the system launches your app extension and instantiates the NEAppPushProvider subclass within that app extension." Source: [login to view URL] We also found a sample code from Apple's documentation, "Receiving Voice and Text Communications on a Local Network" But the sample mentioned that it "Provide voice and text communication on a local network isolated from Apple Push Notification service by adopting Local Push Connectivity." Source: [login to view URL] We want to build a project to send Push Notifications & VoIP Notifications in a local and isolated network using VPN and cellular data only. The scope of work: - Building an iOS app to receive push notification from a privet server in a isolated network and VPN. - Build the backend to send push notification to the isolated iOS devices. Please feel free to ask any additional questions to clarify the task more for you. Thanks.