How does CD work with multiple vendors? For example, I work in a company on a product that reads data from many products of other companies. How do we tell our

How does CD work with multiple vendors? For example, I work in a company on a product that reads data from many products of other companies. How do we tell our customers that we certified the product with the certain version of the products that we read data from? If vendors put change into the production continuously, how can we react to those changes before the customer gets them?