Magento 2.0.18 is the final 2.0.x release. After March 2018, Magento 2.0.x will no longer receive security patches, quality fixes, or documentation updates. To maintain your site's performance, security, and PCIPayment Card Industry: Refers to debit and credit cards and their associated businesses. compliance, upgrade to the latest version of Magento.
Magento Web API
Stores > Settings > Configuration > Services > Magento Web APIApplication Program Interface: A software interface that lets third-party applications read and write to a system using programming language constructs or statements.
Allow Anonymous Guest Access
Determines is guests can anonymously access CMSContent Management System: A software system that is used to create, edit, and maintain content on a website., catalog, and store resources from both SOAP and REST APIs. By default, anonymous guest access is not allowed. Options: Yes / No