Selenium 4.51 Release: What's New and How to Upgrade

Selenium 4.51, released on October 9, 2026 for all major bindings and Grid, primarily changes Java’s ExpectedCondition so that it no longer implements Guava’s Function interface, requiring only code that stores conditions in Guava Function-typed variables, fields, or parameters to switch to java.util.function.Function or ExpectedCondition. Although this removes Guava usage from selenium-support, Guava remains a transitive compile dependency through selenium-remote-driver, with full removal deferred to Selenium 5. The release also adds the @selenium/atoms npm package, JavaScript extension installation and removal through BiDi, Python 3.15 support, Java BiDi code generation, CDP compatibility for versions 153–155, and reliability fixes across bindings and Selenium Manager. Teams upgrading from versions before 4.47 should also account for removed Firefox profile, FTP proxy, HttpClient, file endpoint, and Firefox CDP-related functionality, with Firefox CDP users encouraged to migrate to WebDriver BiDi. Selenium 5 has not been released and remains in a proposed planning stage focused on cross-binding API consistency, BiDi boundaries, asynchronous event APIs, and an independently releasable Selenium Manager.

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