diff --git a/rdp/rdp.h b/rdp/rdp.h
index 88c63d27..2344e591 100644
--- a/rdp/rdp.h
+++ b/rdp/rdp.h
@@ -254,6 +254,7 @@ struct rdp_orders
 struct mod
 {
   int size; /* size of this struct */
+  int version; /* internal version */
   /* client functions */
   int (*mod_start)(struct mod* v, int w, int h, int bpp);
   int (*mod_connect)(struct mod* v);