diff --git a/lms/djangoapps/course_home_api/dates/v1/serializers.py b/lms/djangoapps/course_home_api/dates/v1/serializers.py
index 77245ddfb6..c1f8712f4b 100644
--- a/lms/djangoapps/course_home_api/dates/v1/serializers.py
+++ b/lms/djangoapps/course_home_api/dates/v1/serializers.py
@@ -15,7 +15,7 @@ class DateSummarySerializer(serializers.Serializer):
     Serializer for Date Summary Objects.
     """
     assignment_type = serializers.CharField(default=None)
-    complete = serializers.BooleanField(null=True)
+    complete = serializers.BooleanField(allow_null=True)
     date = serializers.DateTimeField()
     date_type = serializers.CharField()
     description = serializers.CharField()