diff --git a/nbgrader/tests/nbextensions/conftest.py b/nbgrader/tests/nbextensions/conftest.py
index fc8291aee..761bd5303 100644
--- a/nbgrader/tests/nbextensions/conftest.py
+++ b/nbgrader/tests/nbextensions/conftest.py
@@ -186,8 +186,8 @@ def _make_browser(tempdir):
     options = webdriver.firefox.options.Options()
     options.add_argument('-headless')
     options.set_preference('intl.accept_languages', 'en-GB')
-    browser = webdriver.Firefox(
-        options=options, service_log_path=os.path.devnull)
+    service = webdriver.firefox.service.Service(log_path=os.path.devnull)
+    browser = webdriver.Firefox(options=options, service=service)
     browser.set_page_load_timeout(30)
     browser.set_script_timeout(30)