diff --git a/src/documents/serialisers.py b/src/documents/serialisers.py
index 230b94ffe..45bf672d8 100644
--- a/src/documents/serialisers.py
+++ b/src/documents/serialisers.py
@@ -926,6 +926,7 @@ class DocumentSerializer(
             "custom_fields",
             "remove_inbox_tags",
             "page_count",
+            "mime_type",
         )
         list_serializer_class = OwnedObjectListSerializer