To check/verify Magento version of your Magento installation you can login into Magento backend ( http://your-store-name/admin/ ) and scroll down to the footer. Current Magento version should be shown there:
If due to some reason you do not have Magento version shown in the footer it can be checked in Magento Connect Manager:
- switch to Magento Connect Manager at System > Magento Connect > Magento Connect Manager or by pointing your browser to http://your-store-name/downloader/
- check version of Mage_All_Latest package:
As a last resort, Magento version can be checked in app/Mage.php file of your Magento installation, simply search for getVersionInfo() function there:
public static function { return array( 'major' => '1', 'minor' => '6', 'revision' => '1', 'patch' => '0', 'stability' => '', 'number' => '', ); }