How to Check Version of Codeigniter Framework Using

Method 1:
Follow this path : root_folder of CI
Navigate to system -> Core -> Codeigniter.php
Here you can see the version of CI under CI_VERSION constant.
define('CI_VERSION', '3.0.0');

Method 2:
Easy and simple way:
Just write below line in any controller or any view

for example Welcome.php or Index.php (Controller)
In any function or constructor put this:

echo CI_VERSION;

This will give you the version of the CI currently you are using.