diff --git a/filetypes.xml b/filetypes.xml
index 575aba4..3feea72 100644
--- a/filetypes.xml
+++ b/filetypes.xml
@@ -20,6 +20,7 @@
       <mapping ext="opts" type="PLAIN_TEXT" />
       <mapping ext="conf" type="PLAIN_TEXT" />
       <mapping ext="list" type="PLAIN_TEXT" />
+      <mapping ext="old" type="PLAIN_TEXT" />
     </extensionMap>
   </component>
 </application>
\ No newline at end of file