Our use case of sending nudges to clients to check for new Echo messages suggests we should make these messages collapsible. Info on :
A collapsible message is a message that may be replaced by a new message if it has yet to be delivered to the device. [...] Common use cases of collapsible messages are messages used to tell a mobile app to sync data from the server. [...] Only the most recent message is relevant.
We should set the appropriate parameter in message requests: collapseKey for messages to Android.