You may not know what version of WordPress you are using for your site. You can easily find this information. In your File Manager find the domain folder. Click on the wp-includes folder, here you should see a file named version.php.
Select this file and chose view or edit. At the top of this file you will see the version of WordPress.
You can also find this information in the database. In the wp_options table there is a row named db_version. This row will have a strange number in it like 19470.
You can find what database version corresponds to which version of WordPress at WordPress.org