Android : XMPP Library for QT5 to cross platform programming (Android, IOS, Win Phone, B..)

After choosing the XMPP server its time to develop my own XMPP client. My aims to provide a client that can

• send text messages


• Participate in group chat


• make audio and video call


• and maybe send and receive files [Not necessary]

So what is the best XMPP Library for QT5 (i use QT 5.3 if it makes difference) to cross platform programming (for Android, IOS, Windows Phone, Black Berry, Symbian SeriX [and maybe non mobile versions]).

And my noob and important question is

Can all XMPP clients work with all XMPP servers (OpenFire, ejabberd, MongooseIM, Tigase, ...) -> Since maybe we forced to change the server in the future? If not then Is this suitable to programming the client with more classes for communication with library (call the lib methods and etc...) and make us easy to change the lib when the server changed?

And if you give me down vote please tell me Why.