It is possible to quickly find the CMS or the payment module version without signing into your CMS.
Sign in to the Merchant Back Office.
Go to the menu Management > Transactions or TEST transactions.
Search for a payment that has been made from the CMS and double click or right click on it > Display transaction details.
Go to the Details tab.
In the Source details section, search for the value corresponding to the E-commerce solution label.
Example: Magento_2.x_v2.5.4/2.4.2/7.2.15.
Magento_2.x_v2.5.4: corresponds to the name of the payment module, 2.5.4 is the module version.
2.4. 2 corresponds to the CMS version. 7.2.15 corresponds to the PHP version of your server.