Conversations works with every XMPP server out there. However XMPP is an extensible protocol. These extensions are standardized as well in so called XEP’s. Conversations supports a couple of those to make the overall user experience better. There is a chance that your current XMPP server does not support these extensions, please see the compliance list for an update list. Therefore to get the most out of Conversations you should consider either switching to an XMPP server that does or - even better - run your own XMPP server for you and your friends.
Downloading and Installing Conversations
Conversations is for the Android operating system and is available for purchase on the google play store for $2.49. You can install Conversations as you would any other app on an Android phone/tablet.