title: How to upgrade Qt installed in linux from one version to higher
body: <p>While porting Qt project from windows to linux(ubuntu) i faced with the following issue:</p>
  
  <p>on <strong>windows Qt version 4.8.1</strong> is installed
  on <strong>linux 4.6.3</strong> in which some functionalities availiable in higer version 4.8.1 <strong>don`t yet implemented</strong> (ex. <strong>QUdpSocket::joinMultiCastGroup</strong>).</p>
  
  <p>I see only one solution to this problem: upgrade Qt version on linux to 4.8.1.
  <strong>How can I do this?</strong></p>
  
  <p><em>On linux I got installed libqt4-dev, qmake.</em></p>