--- ./extend_helper.ml
+++ ./extend_helper.ml
@@ -1,13 +1,6 @@
-(*pp cppo -V OCAML:`ocamlc -version` *)
 open Parsetree
 open Extend_protocol
 
-#if OCAML_VERSION < (4, 3, 0)
-# define CONST_STRING Asttypes.Const_string
-#else
-# define CONST_STRING Parsetree.Pconst_string
-#endif
-
 (** Default implementation for [Reader_def.print_outcome] using
     [Oprint] from compiler-libs *)
 let print_outcome_using_oprint ppf = function
@@ -28,7 +21,7 @@
       pstr_loc = Location.none;
       pstr_desc = Pstr_eval ({
           pexp_loc = Location.none;
-          pexp_desc = Pexp_constant (CONST_STRING (msg, None));
+          pexp_desc = Pexp_constant (Parsetree.Pconst_string (msg, None));
           pexp_attributes = [];
         }, []);
     }]
@@ -112,7 +105,7 @@
   let msg = match payload with
     | PStr [{
         pstr_desc = Pstr_eval ({
-            pexp_desc = Pexp_constant (CONST_STRING (msg, _));
+            pexp_desc = Pexp_constant (Parsetree.Pconst_string (msg, _));
           }, _);
       }] -> msg
     | _ -> "Warning: extension produced an incorrect syntax-error node"