diff --git a/cli/fathom_web/vectorizer.py b/cli/fathom_web/vectorizer.py
index 0137a103..c8dc038e 100644
--- a/cli/fathom_web/vectorizer.py
+++ b/cli/fathom_web/vectorizer.py
@@ -26,6 +26,7 @@
 from filelock import FileLock
 from selenium import webdriver
 from selenium.common.exceptions import NoSuchElementException, NoSuchWindowException
+from selenium.webdriver.common.by import By
 from selenium.webdriver.support.ui import Select
 
 from .utils import read_chunks, samples_from_dir
@@ -398,23 +399,27 @@ def running_firefox(fathom_fox, show_browser, geckodriver_path):
 
     """
     print('Running Firefox...', end='', flush=True)
-    options = webdriver.FirefoxOptions()
-    options.headless = not show_browser
 
     with TemporaryDirectory() as download_dir:
-        profile = webdriver.FirefoxProfile()
-        profile.set_preference('browser.download.folderList', 2)
-        profile.set_preference('browser.download.dir', download_dir)
-        profile.set_preference('browser.cache.disk.enable', False)
-        profile.set_preference('browser.cache.memory.enable', False)
-        profile.set_preference('browser.cache.offline.enable', False)
-        profile.set_preference('devtools.chrome.enabled', True)
+        options = webdriver.FirefoxOptions()
 
-        firefox = webdriver.Firefox(
+        if not show_browser:
+            options.add_argument('-headless')
+
+        options.set_preference('browser.download.folderList', 2)
+        options.set_preference('browser.download.dir', download_dir)
+        options.set_preference('browser.cache.disk.enable', False)
+        options.set_preference('browser.cache.memory.enable', False)
+        options.set_preference('browser.cache.offline.enable', False)
+        options.set_preference('devtools.chrome.enabled', True)
+
+        service = webdriver.firefox.service.Service(
             executable_path=str(geckodriver_path.resolve()),
+            log_path=devnull,
+        )
+        firefox = webdriver.Firefox(
+            service=service,
             options=options,
-            firefox_profile=profile,
-            service_log_path=devnull,
         )
 
         firefox.install_addon(str(fathom_fox), temporary=True)
@@ -466,7 +471,7 @@ def run_vectorizer(firefox, trainee_id, sample_filenames, output_path, kind_of_s
     """
     def put_into_field(field_id, string):
         """Put a given string into the text field of a given ID."""
-        field = firefox.find_element_by_id(field_id)
+        field = firefox.find_element(By.ID, field_id)
         field.clear()
         field.send_keys(string)
 
@@ -475,7 +480,7 @@ def put_into_field(field_id, string):
     fathom_fox_uuid = get_fathom_fox_uuid(firefox)
     firefox.get(f'moz-extension://{fathom_fox_uuid}/pages/vector.html')
 
-    ruleset_dropdown_selector = Select(firefox.find_element_by_id('trainee'))
+    ruleset_dropdown_selector = Select(firefox.find_element(By.ID, 'trainee'))
     try:
         ruleset_dropdown_selector.select_by_visible_text(trainee_id)
     except NoSuchElementException:
@@ -487,8 +492,8 @@ def put_into_field(field_id, string):
     put_into_field('maxTabs', str(tabs))
 
     number_of_samples = len(sample_filenames)
-    status_box = firefox.find_element_by_id('status')
-    vectorize_button = firefox.find_element_by_id('freeze')
+    status_box = firefox.find_element(By.ID, 'status')
+    vectorize_button = firefox.find_element(By.ID, 'freeze')
     completed_samples = 0
     print('done.')
 
@@ -511,7 +516,7 @@ def put_into_field(field_id, string):
             completed_samples = now_completed_samples
             sleep(.25)
 
-    download_dir = Path(firefox.profile.default_preferences['browser.download.dir'])
+    download_dir = Path(firefox.options.preferences['browser.download.dir'])
     new_file = wait_for_vectors_in(download_dir)
     unlink_if_exists(output_path)  # move() won't overwrite a file on Windows.
     output_path.parent.mkdir(parents=True, exist_ok=True)
diff --git a/cli/setup.py b/cli/setup.py
index 87e3148b..f95a0d72 100644
--- a/cli/setup.py
+++ b/cli/setup.py
@@ -18,7 +18,7 @@
         'numpy>=1.18.1,<1.24.0',
         'filelock>=3.0.12',
         'scikit-learn>=0.22.2',
-        'selenium>=3.141.0',
+        'selenium>=4.10.0,<5.0',
         'tensorboardX>=1.6,<2.0',
         'torch>=1.0,<2.0',
         'protobuf <= 3.20.1',