diff --git a/datamodel-default.yml b/datamodel-default.yml
index 9c618ed9cadb586ed1e3d16879661a9e5c5cdf0b..b3271416adfdb6bd23a1ced355c3850b81eefb70 100644
--- a/datamodel-default.yml
+++ b/datamodel-default.yml
@@ -58,5 +58,9 @@ Loan:
       datatype: DATETIME
     returned:
       datatype: DATETIME
+    returned Box version:
+      datatype: Box
+    borrowed Box version:
+      datatype: Box
 Location: