After a long wait, Skype had unexpectedly released an update of Skype for Linux on 14th of June this year. This update made Skype to come out of beta and added great features like a new conversation view, new call view, few bug fixes and over all improvement in video call quality.
While Skype 4 was available for download from their website in .deb format, users could only install older version of Skype from Ubuntu Software Center.
However, Skype 4 is available from USC now. To install it, you need to update the sources of apt with the following command:
sudo apt-get update
After that, search Skype in the software center and you will be able to install it right away.