Selenium 4 is a standards-based protocol using the W3C WebDriver standard for browser automation, ensuring future-proof support across all browsers. It introduces relative locators, new window and tab utilities, and features like printing pages as PDFs with Chrome and Firefox. The upcoming version also exposes new features with Firefox, modifies network conditions in Chromium-based browsers, and adds two new methods for getting element attributes or properties. Selenium Grid 4 has been rewritten from scratch, leveraging modern infrastructure such as Docker and distributed tracing. While some minor changes may be needed to existing tests, they will continue to run on Sauce Labs' platform if updated accordingly.