diff --git a/_Main.cs b/_Main.cs
index 29f7f92..9d47f0e 100644
--- a/_Main.cs
+++ b/_Main.cs
@@ -1218,7 +1218,7 @@ namespace bdf
                         //Store output docs as memorystreams and deal with them all at once
                         try
                         {
-                            workbook.SaveToStream(bdf_as_ms);
+                            workbook.SaveToStream(bdf_as_ms, FileFormat.Version2016);
                         }
                         catch (Exception e)
                         {