Methods and apparatuses that generate a subtopic identifier identifying a client application within a client device that can support multiple users are described. The client application may be associated with a server application hosted in one or more application servers. Notification services may be registered with the application servers from the client application to forward identifiers associated with the client application for one of the multiple users to the server application to enable the server application to push notification messages to the client device selectively for the client application for that user. When receiving a notification message from the application server, the notification message may be examined to forward the notification message directly to the client application for that user without invoking other applications in the client device if the notification message carries a subtopic identifier of the client application.