There are several ways to check the version of Magento that you are currently running:
Check the footer of the Magento admin panel: Log in to the Magento admin panel, and look at the bottom of the page. The version number should be displayed in the footer.
Check the “Magento Connect Manager”: Log in to the Magento Connect Manager (yoursite.com/downloader), and look for the version number in the top right corner of the page.
Check the codebase: you can check the version of Magento by looking at the version number in the app/Mage.php file.
Check the database: You can check the version of Magento by running the following SQL query in your database: “SELECT * FROM core_resource WHERE code = ‘core_setup'”
Check the composer.json file: If you installed Magento using composer, you can check the version in the composer.json file located in the root directory of your Magento installation
Use a Magento version checker extension: There are several Magento version checker extensions available that can help you quickly and easily check the version of Magento that you are running.
It is important to keep your Magento installation up to date with the latest version to ensure the best security and performance.