The easiest way to find the Opencart version that you are running is to see at the admin footer. Go to your site http://YOUR_URL/admin then see at the footer and you will be able to know which version of opencart it is because most of the programmer did not remove it, so it will be easy to find it out.
If you were not able to find it there then another option is to open the index.php of the root folder and look for
// Version
define('VERSION', '3.0.3.2');
The VERSION is the named constant for the Opencart version, here in the above example it is 3.0.3.2
Similarly, there are other places where we can find the Opencart version. We can also find it out by seeing the coding style also. One of the most changed styles is as below,
Open ../catalog/controller/module/latest.php, look at line 3
If it says: protected function index($module) { then you have 1.5.0.x
If it says: protected function index($setting) { then you have 1.5.1.x
Similarly, you can find out the opencart version, let us know if you are having any issues and we will help you on those.
