PHP version 5.6 or newer is recommended. It should

This page describes some “best practices” regarding web security, and details CodeIgniter’s internal security features.

CodeIgniter’s Hooks feature provides a means to tap into and modify the inner workings of the framework without hacking the core files. When CodeIgniter runs it follows a specific

Every time CodeIgniter runs there are several base classes that are initialized automatically as part of the core framework. It is possible, however, to swap any of the core