diff --git a/competition/serializers.py b/competition/serializers.py
index 0b9bf7c..4e0262b 100644
--- a/competition/serializers.py
+++ b/competition/serializers.py
@@ -292,7 +292,7 @@ def get_series_num_solutions(self, obj):
 
 
 @ts_interface(context='competition')
-class SeriesWithProblemsSerializer(serializers.ModelSerializer):
+class SeriesWithProblemsSerializer(ModelWithParticipationSerializer):
     problems = ProblemSerializer(
         many=True,
         read_only=True