diff --git a/awx/api/serializers.py b/awx/api/serializers.py
index 106e4b0198..c6553508fa 100644
--- a/awx/api/serializers.py
+++ b/awx/api/serializers.py
@@ -343,6 +343,8 @@ class BaseSerializer(serializers.ModelSerializer):
                     continue
                 summary_fields[fk] = OrderedDict()
                 for field in related_fields:
+                    if field == 'credential_type_id' and fk == 'credential' and self.version < 2:
+                        continue
 
                     fval = getattr(fkval, field, None)