iOS Question Chat

It will be much easier to answer if you will ask specific question )) maybe I can give you some advice as I am also developing a chat inside my app.

Ok.
Let's say user's A car broke down. There would be an option in my app to join a chat inside my app, so he would write there something like: Hey my car broke down, I need help. And other loged-in users in the app would get the notification about new message in chat and they could respond. Something like that.
What solution have you made?

Thanks,
G

My solution is based on B4J, jServer with Websockets. But I think for your situation jMQTT is better.