Install Open Source Social Network on Ubuntu 16.04

In this tutorial, we are going to provide you with step by step instructions on how to install Open Source Social Network with Apache on an Ubuntu 16.04 VPS.
Open Source Social Network (OSSN) is a social networking software written in PHP used by website developers to create social networking websites. The installation process is easy and it takes only a couple of minutes.

At the time of writing this tutorial, the latest stable version of Open Source Social Network is 4.2 and it requires:

PHP 5.4 or higher (preferably the latest), compiled with cURL, mcrypt, MySQLi, ZIP, JSON, XML PHP extensions and GD PHP Library enabled.
allow_url_fopen option enabled in PHP
Apache Web Server 2.0 or higher compiled with mod_rewrite module;

This install guide assumes that Apache is already installed and configured on your virtual server.