A network element of a communication provider, comprising: transceiver apparatus arranged to receive a request message from an originating endpoint via a packet-based communication network; and processing apparatus configured to generate, in response to the request message from the originating endpoint, a push notification relating to a communication from the originating endpoint intended for a destination endpoint to notify a destination user of the destination endpoint of the communication, the communication to be conducted over the packet-based network; and wherein the transceiver apparatus is arranged to send the push notification to the destination endpoint over the packet-based network; wherein the processing apparatus is configured to generate the push notification with a payload comprising an indication of an image representing an originating user of the originating endpoint, to be output by the destination endpoint in a user notification notifying the destination user regarding the communication, at least said indication of the image being determined and inserted into the payload of the push notification at said network element; the network element characterised in that: the push notification comprises an operating system based push notification; the processing apparatus and transceiver apparatus of the network element are further configured to send the operating system based push notification to the destination endpoint via a separate network element of an operating system based push notification service; and the destination endpoint comprises a communication client application which at times is found in a background state whereby it is suspended or scheduled a suppressed number of processing cycles by an operating system of the destination endpoint, wherein the push notification is configured to initiate wake up of the communication client application from the background state. transceiver apparatus arranged to receive a request message from an originating endpoint via a packet-based communication network; and processing apparatus configured to generate, in response to the request message from the originating endpoint, a push notification relating to a communication from the originating endpoint intended for a destination endpoint to notify a destination user of the destination endpoint of the communication, the communication to be conducted over the packet-based network; and wherein the transceiver apparatus is arranged to send the push notification to the destination endpoint over the packet-based network; wherein the processing apparatus is configured to generate the push notification with a payload comprising an indication of an image representing an originating user of the originating endpoint, to be output by the destination endpoint in a user notification notifying the destination user regarding the communication, at least said indication of the image being determined and inserted into the payload of the push notification at said network element; the network element characterised in that: the push notification comprises an operating system based push notification; the processing apparatus and transceiver apparatus of the network element are further configured to send the operating system based push notification to the destination endpoint via a separate network element of an operating system based push notification service; and the destination endpoint comprises a communication client application which at times is found in a background state whereby it is suspended or scheduled a suppressed number of processing cycles by an operating system of the destination endpoint, wherein the push notification is configured to initiate wake up of the communication client application from the background state. the push notification comprises an operating system based push notification; the processing apparatus and transceiver apparatus of the network element are further configured to send the operating system based push notification to the destination endpoint via a separate network element of an operating system based push notification service; and the destination endpoint comprises a communication client application which at times is found in a background state whereby it is suspended or scheduled a suppressed number of processing cycles by an operating system of the destination endpoint, wherein the push notification is configured to initiate wake up of the communication client application from the background state.