From Firefox 48 it is necessary to use GeckoDriver [1] for web based automation using Selenium. This bug will track the work needed to switch our automation to GeckoDriver. [1] https://github.com/mozilla/geckodriver

We upgraded moz-grid-config to Selenium 3.0b2 with GeckoDriver 0.10.0: https://github.com/mozilla/moz-grid-config/commit/9b527586a5e97fc7f2043d4eac8a8da0f7d91867 https://github.com/mozilla/moz-grid-config/commit/93d25b73a2543aee35aac64ddb914ba3b60e08dd This is now running in staging and production: http://selenium-hub-staging1.qa.scl3.mozilla.com:4444/grid/console http://selenium-hub1.qa.scl3.mozilla.com:4444/grid/console We've also switched one of our suites to use GeckoDriver: https://github.com/mozilla/hello-tests/commit/05e402b00485013c783231c8221f9f9b732cf374

At this time I believe Mozillians has switched to latest Firefox release (51), and that Bedrock have at least tried to update. Unfortunately GeckoDriver/Marionette is not yet fully compliant with the WebDriver spec, however I understand that most remaining issues are targeted to be fixed in Firefox 52. My current recommendation would be to hold off updating until Firefox 52 is released. I will keep myself assigned to this bug and will provide an update once Firefox 52 is released.

I think it’s unlikely that we will get all specification compatibility issues fixed in Marionette by 52, but you can follow the current status on https://developer.mozilla.org/en-US/docs/Mozilla/QA/Marionette/WebDriver/status.

I have raised blocking bugs for the suites that remain to be migrated to a modern Firefox version. Bedrock (https://github.com/mozilla/bedrock/pull/4472) and Kuma (https://github.com/mozilla/kuma/pull/4195) are blocked by https://github.com/SeleniumHQ/selenium/issues/3808, which should be resolved when Selenium 3.5 is released.

All active suites are now using GeckoDriver and recent Firefox releases.