Some time you don’t know you are working on which version of magento. So if you want to see the version of magento using code follow below steps.
Step 1 : create one checkversion.php file in root directory of your magento project.
Step 2 : Now copy and paste the below code.
<?php include_once(‘app/Mage.php’); Mage::app(); echo Mage::getVersion(); ?>
When you include Mage.php you are ready to access all core classes of magento.
Mage::app() function is used to bootstrap your Magento application (setting up configuration, autoloading etc) and is useful when wanting to access Magento models in your own custom script for example.