Note that Prosody has a UnifiedPush community module that is simple to enable. This can save you from running one extra specialized server & one extra always-on connection provided you were already runnnig an XMPP server.
It feels a bit like a Scooby Doo reveal when you use Prosody + a Conversation fork seeing UnifiedPush is all powered by XMPP since it accomplishes the same task of a push-based messaging.