Selenium 4 introduces several enhancements over its predecessor, Selenium 3, including W3C compliance for WebDriver APIs, which leads to more stable cross-browser tests, and new features like relative locators, an improved Selenium Grid, and a revamped Selenium IDE. The update marks the deprecation of the JSON Wire Protocol in favor of the W3C protocol and removes native support for Opera and PhantomJS browsers. The Selenium Grid now supports IPv6, HTTPS, and configuration with TOML language, while the IDE extends compatibility to major browsers such as Chrome and Firefox, incorporating a control-flow mechanism and allowing code export for multiple languages. Additionally, Selenium 4 offers enhanced documentation and Chrome DevTools Protocol support for better debugging and performance analysis. Significant changes include the replacement of DesiredCapabilities with Options objects and the introduction of new methods in the Actions class. Despite being in the Alpha stage, Selenium 4 is seen as a significant evolution that simplifies and accelerates testing processes.