Selenium 4 has started its development in late 2018 and was released on October 13, 2021. The new release includes several features such as relative locators, better window and tab management, improved Selenium Grid, use of W3C by default under the hood, a set of bidirectional APIs designed for intercepting network requests, authentication on secure pages, listening to DOM events, and more. Selenium 4 is designed to be a drop-in replacement, but some tests or dependencies may need adjustments. Sauce Labs has contributed to its development, ensuring that tests will continue to work on their platform. The upgrade process to Selenium 4 is considered relatively painless, with some deprecated features to consider during the transition. The new release includes various new features such as relative locators, new window and tab utilities, printing pages as PDFs, network conditions setting, new element attribute and property methods, and bidirectional APIs.