In the past, some electronic devices were thought to only be able to read e-books, such as the Kindle and eReader. However, as time went on, more and more electronic products were developed that could read and support e-books in multiple format at the same time, such as Android and iPhone devices, tablets, and smart phones. With the development of technology, the format of e-books is constantly updated and evolved. Some e-book format is no longer widely used. Therefore, even an electronic product that could only read e-books could gradually be eliminated in the future.