title: How to update Qt from 5.5.1 to 5.7 on Ubuntu 16.04?
body: <p>I am trying to update Qt from 5.5.1 to 5.7 or higher.</p>
  <p>I tried <code>sudo apt-get install qt-default qtdeclarative5-dev </code>
  gives me following output on console:</p>
  <blockquote>
  <p>qtdeclarative5-dev is already the newest version (5.5.1-2ubuntu6).</p>
  <p>qt5-default is already the newest version (5.5.1+dfsg-16ubuntu7.6).</p>
  </blockquote>
  <p>How can I update Qt to 5.7 or higher version?</p>