diff --git a/plinth/modules/config/tests/test_functional.py b/plinth/modules/config/tests/test_functional.py
index 0b3ee1a37..aabebdf2b 100644
--- a/plinth/modules/config/tests/test_functional.py
+++ b/plinth/modules/config/tests/test_functional.py
@@ -4,6 +4,7 @@ Functional, browser based tests for config app.
 """
 
 import pytest
+
 from plinth.tests import functional
 
 pytestmark = [
@@ -61,8 +62,7 @@ def _set_home_page(browser, home_page):
     functional.nav_to_module(browser, 'config')
     drop_down = browser.find_by_id('id_homepage')
     drop_down.select(home_page)
-    update_setup = browser.find_by_css('.btn-primary')
-    functional.submit(browser, element=update_setup)
+    functional.submit(browser, form_class='form-configuration')
 
 
 def _check_home_page_redirect(browser, app_name):
diff --git a/plinth/modules/upgrades/tests/test_functional.py b/plinth/modules/upgrades/tests/test_functional.py
index 61c68cc63..61a64375d 100644
--- a/plinth/modules/upgrades/tests/test_functional.py
+++ b/plinth/modules/upgrades/tests/test_functional.py
@@ -4,6 +4,7 @@ Functional, browser based tests for upgrades app.
 """
 
 import pytest
+
 from plinth.tests import functional
 
 pytestmark = [pytest.mark.system, pytest.mark.essential, pytest.mark.upgrades]
@@ -51,8 +52,7 @@ def _enable_automatic(browser, should_enable):
     else:
         checkbox_element.uncheck()
 
-    update_setup = browser.find_by_css('.btn-primary')
-    functional.submit(browser, element=update_setup)
+    functional.submit(browser, form_class='form-configuration')
 
 
 def _get_automatic(browser):
diff --git a/plinth/tests/functional/__init__.py b/plinth/tests/functional/__init__.py
index 508c4980d..002132d26 100644
--- a/plinth/tests/functional/__init__.py
+++ b/plinth/tests/functional/__init__.py
@@ -441,8 +441,7 @@ def app_can_be_disabled(browser, app_name):
 def set_domain_name(browser, domain_name):
     nav_to_module(browser, 'config')
     browser.find_by_id('id_domainname').fill(domain_name)
-    update_setup = browser.find_by_css('.btn-primary[type="submit"]')
-    submit(browser, element=update_setup)
+    submit(browser, form_class='form-configuration')
 
 
 ########################
@@ -493,8 +492,7 @@ def running_inside_container():
 def set_hostname(browser, hostname):
     nav_to_module(browser, 'config')
     browser.find_by_id('id_hostname').fill(hostname)
-    update_setup = browser.find_by_css('.btn-primary')
-    submit(browser, element=update_setup)
+    submit(browser, form_class='form-configuration')
 
 
 def set_advanced_mode(browser, mode):
@@ -505,8 +503,7 @@ def set_advanced_mode(browser, mode):
     else:
         advanced_mode.uncheck()
 
-    update_setup = browser.find_by_css('.btn-primary')
-    submit(browser, element=update_setup)
+    submit(browser, form_class='form-configuration')
 
 
 ####################