The following table shows a mapping between geckodriver releases, supported versions of Firefox, and required Selenium version:
|geckodriver||Selenium||Supported versions of Firefox|
|0.23.0||≥ 3.11 (3.14 Python)||57||n/a|
|0.22.0||≥ 3.11 (3.14 Python)||57||n/a|
|0.21.0||≥ 3.11 (3.14 Python)||57||n/a|
geckodriver is not yet feature complete. This means that it does not yet offer full conformance with the WebDriver standard or complete compatibility with Selenium. You can track the implementation status of the latest Firefox Nightly on MDN. We also keep track of known Selenium, remote protocol, and specification problems in our issue tracker.
Support is best in Firefox 57 and greater, although generally the more recent the Firefox version, the better the experience as they have more bug fixes and features. Some features will only be available in the most recent Firefox versions, and we strongly advise using the latest Firefox Nightly with geckodriver. Since Windows XP support in Firefox was dropped with Firefox 53, we do not support this platform.