diff --git a/apps/api/templates/api/includes/addon.xml b/apps/api/templates/api/includes/addon.xml
index b895723b80..70e669caf2 100644
--- a/apps/api/templates/api/includes/addon.xml
+++ b/apps/api/templates/api/includes/addon.xml
@@ -46,7 +46,7 @@
   {%- if api_version >= 1.5 -%}
   <previews>
     {%- for preview in addon.previews.all() -%}
-    <preview primary="{{ preview.highlight }}">
+    <preview primary="{{ preview.highlight|int }}">
       <full type="{{ preview.filetype }}">
         {{ preview.image_url|urlparams(src='api') }}
       </full>
diff --git a/apps/translations/transformer.py b/apps/translations/transformer.py
index 24904a770b..9b54812e80 100644
--- a/apps/translations/transformer.py
+++ b/apps/translations/transformer.py
@@ -5,6 +5,7 @@ from django.utils import translation
 import multidb
 
 from translations.models import Translation
+from translations.fields import TranslatedField
 
 isnull = """IF(!ISNULL({t1}.localized_string), {t1}.{col}, {t2}.{col})
             AS {name}_{col}"""
@@ -24,6 +25,10 @@ def build_query(model, connection):
     else:
         fallback = settings.LANGUAGE_CODE
 
+    if not hasattr(model._meta, 'translated_fields'):
+        model._meta.translated_fields = [f for f in model._meta.fields
+                                         if isinstance(f, TranslatedField)]
+
     # Add the selects and joins for each translated field on the model.
     for field in model._meta.translated_fields:
         # Add the primary and (possibly) fallback locale parameters.