Selenium 4.42 Released!

Today we’re happy to announce that Selenium 4.42 has been released!

By Diego Molina @diemol | Thursday, April 09, 2026

Selenium 4.42 Released

[.NET] A large BiDi consistency pass: unified event arguments, exposed BiDi functionality via interfaces, thread-safe event registration and processing, and commands/events that allocate close to nothing.
[Java] Implemented the BiDi speculation module, continued JSpecify nullability coverage (chromium, browsers, grid, devtools, docker packages), and fixed several Keys/ScriptKey correctness issues.
[Grid] Hardened the WebSocket router: a transparent TCP tunnel bypass path, handling for dropped close frames and idle disconnects, and a new NodeCommandInterceptor for pluggable command interception via --ext.
[Python] Expanded BiDi test coverage and added type stubs for lazily imported classes.
[JavaScript] Added a Color class to the JavaScript library.
[Build] Bumped to Bazel 9.

Implemented the BiDi speculation module.
Continued JSpecify nullability annotations across the chrom*, browsers, grid.*, devtools, and docker packages.
Deduplicated Unicode PUA mappings in Keys, made OPTION an alias of ALT, and deprecated FN.
Fixed a regression that unnecessarily serialized binary streams in RemoteWebDriver.builder(), and guarded against an NPE in Platform.extractFromSysProperty.
Enhanced ScriptKey.toString() and masked script content in UnpinnedScriptKey.

Expanded BiDi test coverage.
Added type stubs for lazily imported classes and modules.
Added a module for importing the latest DevTools version, and stopped closing externally provided log_output streams.

Unified all BiDi event arguments to a consistent *EventArgs type, and exposed BiDi functionality via interfaces.
Made event registration and command/event processing thread-safe, with close to zero allocation per command/event.
Properly handled the WebSocket close handshake, and made any WebDriver disposable asynchronously.
Bumped the C# language version to 14.0.

Added a transparent TCP tunnel bypass path for the WebSocket data path in the Router.
Handled dropped close frames, idle disconnects, and high-latency proxying in the Router WebSocket.
Added NodeCommandInterceptor for pluggable command interception via --ext.
Fixed VNC capabilities not being propagated for sessions without a browserName.