diff --git a/bsmain/utils.py b/bsmain/utils.py
index 4d63ae8..80207af 100644
--- a/bsmain/utils.py
+++ b/bsmain/utils.py
@@ -1,6 +1,7 @@
 import os
 import stat
 import logging
+from django.template.defaultfilters import yesno as broken_yesno
 
 from .future_python import makedirs
 
@@ -100,3 +101,13 @@ def b108_makedirs(path):
             break
 
         current = parent
+
+
+def yesno(value, arg=None):
+    """
+    See https://code.djangoproject.com/ticket/36579
+    """
+    result = broken_yesno(value, arg)
+    if result is None:
+        return "Maybe"
+    return result
diff --git a/projects/forms.py b/projects/forms.py
index 2bc2861..9f8f37a 100644
--- a/projects/forms.py
+++ b/projects/forms.py
@@ -1,12 +1,12 @@
 from django import forms
 from django.contrib.auth import get_user_model
-from django.template.defaultfilters import yesno
 from django.urls import reverse
 from django.utils.translation import gettext_lazy as _
 from django.utils.html import format_html
 
 from bugsink.utils import assert_
 from teams.models import TeamMembership
+from bsmain.utils import yesno
 
 from .models import Project, ProjectMembership, ProjectRole
 
diff --git a/teams/forms.py b/teams/forms.py
index dbf0bd3..8541397 100644
--- a/teams/forms.py
+++ b/teams/forms.py
@@ -1,9 +1,9 @@
 from django import forms
 from django.contrib.auth import get_user_model
-from django.template.defaultfilters import yesno
 from django.utils.translation import gettext_lazy as _
 
 from bugsink.utils import assert_
+from bsmain.utils import yesno
 from .models import TeamRole, TeamMembership, Team
 
 User = get_user_model()