diff --git a/src/vim.h b/src/vim.h
index 6533a45..265fd73 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2130,7 +2130,8 @@
 #define VV_SIZEOFLONG	103
 #define VV_SIZEOFPOINTER 104
 #define VV_MAXCOL	105
-#define VV_LEN		106	// number of v: vars
+#define VV_PYTHON3_VERSION 106
+#define VV_LEN		107	// number of v: vars
 
 // used for v_number in VAR_BOOL and VAR_SPECIAL
 #define VVAL_FALSE	0L	// VAR_BOOL