title: Can I merge Bootstrap 2.3.1 with new versions like 4.0 or 3.x.x?
body: <p>I have a website in that I used bootstrap 2.3.1. Now I want to change the version and I want to update. If I updated the bootstrap with new version.
  Total UI is changing. <strong>Website turning into clumsy</strong>. So my intention is to just merge the previous bootstrap file with new one without removing the previous attributes and just updating the new content.</p>