The Xelion server can send push messages to Xelion apps. This is used on the Android and iOS app to receive information about incoming/missed calls/chats and otger information.
For example, when a new call is incoming, the APP receives an incoming call push notification to update the local addressbook or registering the SIP client.

Checkout the Changelog regulary for changes in the Xelion push messages.

Push messages are only send to iOS and Android devices.
If this is needed, then the app needs to be registered with the call Register Device
Don’t forget to give the push service information when registering.