Push notifications in a local network

I need to implement Push Notifications for Android and iOS using my own server in a local network with no Internet access. More precisely, my users will have a mobile app (Android and iOS) which will connect to a local Server through a wireless network. This network won’t have any Internet connection. The server will need to send push notifications to the connected devices when some concrete events happen.

I’m using Django on the server side.

I’ve been researching a bit and it looks like using XMPP would be a neat solution. Thus I guess I need an XMPP Server to communicate with the mobile devices. I’ve seen several alternatives for the server side, though I don’t understand completely what I need exactly. There are some XMPP servers such as Openfire and SleekXMPP. I’m not really sure what are they for. Should I choose one of them or use both?

On the other side, which alternatives are there in the app side?

What I need basically is some guidance on which technologies to choose and some references.

Did you archieve anything? I’m basically in the same situation and would appreciate some help.
Thank you