diff --git a/src/plugins/wp/wp_parameters.ml b/src/plugins/wp/wp_parameters.ml
index 38c898654f4ac51b3d37cb85bbe5d1e2c80b11e4..87e0a0e59fb8e235300525eb4c570f89474260ed 100644
--- a/src/plugins/wp/wp_parameters.ml
+++ b/src/plugins/wp/wp_parameters.ml
@@ -57,7 +57,7 @@ let () = on_reset WP.clear
 
 let () = Parameter_customize.set_group wp_generation
 module Legacy =
-  True(struct
+  False(struct
     let option_name = "-wp-legacy"
     let help = "Use legacy generator engine."
   end)