Selenium 4.50 Released!

Today we’re happy to announce that Selenium 4.50 has been released!

By Diego Molina @diemol | Wednesday, September 30, 2026

Selenium 4.50 Released

Relative locators in Java and .NET can now be anchored to elements and shadow roots, not just the driver.
Firefox deprecated profile extension and certificate methods were removed from every binding, and Java, Python, and .NET now declare Firefox default preferences in the binding itself.
BiDi .NET added screenshot image size, a screencast destination folder, Emulation.SetTextLayoutModeOverride, and activity source monitoring; Ruby can now install and uninstall web extensions through BiDi; Java parses each BiDi command response only once.
[Java] Removed deprecated methods from the HttpClient interface, and a RemoteWebDriver now uses a single HttpClient.Factory.
[Python] ClientConfig user_agent and extra_headers are now applied per connection.
[Build & Infra] Releases are now built on RBE, Selenium Manager can be cross-compiled for all platforms from Linux or Mac, and the BiDi schema is generated from more upstream sources, including Mozilla’s Firefox CDDL.

Supported relative locators from elements and shadow roots (shared with .NET).
Removed deprecated methods from the HttpClient interface; the HttpCommandExecutor client and httpClientFactory fields were restored as deprecated to ease the transition.
Used one HttpClient.Factory per RemoteWebDriver instance.
Resolved exceptions from the W3C error state in ErrorHandler, and kept guarded runnables alive when a task throws an Error.
Parsed each BiDi command response once, and cleared fetchError and realm listeners when closing Network and Script.

Applied ClientConfig user_agent and extra_headers per connection.
Typed BaseOptions.set_capability and WebElement.get_attribute parameters.
Cleaned up exception chaining for ruff rule B904.
Moved the full GitHub Actions test suite to nightly runs, keeping fast smoke tests on PRs, and ran Grid specific tests on Windows during scheduled runs.

Supported relative locators from elements and shadow roots (shared with Java).
Added BiDi screenshot image size, a DestinationFolder option for StartScreencast, Emulation.SetTextLayoutModeOverride, activity source monitoring, and hasPlannedNavigation in ContextCreatedEventArgs.
Removed BiDi context from the hot path, preserved additional data in context commands, and aligned the CapabilityResponse type name with the spec.
NuGet packages now include license and notice files.

Built release artifacts on RBE, and automatically merged the release PR once required checks pass.
Added a Bazel flag to cross-compile all Selenium Manager binaries from Linux or Mac, and moved Selenium Manager publishing into the snapshot workflow so releases no longer skip it.
Generated the BiDi schema from the spec’s external specifications list, Mozilla’s Firefox CDDL, and its Commands fragment.
Added ADRs for a network async/event API and a behavioral contract for the low-level BiDi layer.
Selenium Manager now shows a proper error message when the metadata file can’t be opened.