diff --git a/GT.opam b/GT.opam
index a1d0b9c0..4ab609db 100644
--- a/GT.opam
+++ b/GT.opam
@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "0.5.3"
+version: "0.5.5"
 synopsis: "Generic programming with extensible transformations"
 description: """
 Yet another library for generic programming. Provides syntax extensions
@@ -22,10 +22,10 @@ license: "LGPL-2.1-or-later"
 homepage: "https://github.com/PLTools/GT"
 bug-reports: "https://github.com/PLTools/GT/issues"
 depends: [
-  "ocaml" {>= "4.14" & < "5.0.0" | >= "5.2.0" & < "5.3.0"}
+  "ocaml" {>= "4.14" & < "5.0.0" | >= "5.2.0" & <= "5.4.0"}
   "dune" {>= "3.16"}
   "ppxlib" {<= "0.34.0"}
-  "camlp5" {>= "8.00.05"}
+  "camlp5" {>= "8.04.00"}
   "ocamlgraph"
   "ppx_inline_test_nobase"
   "mdx" {build}
diff --git a/camlp5/Camlp5Helpers.ml b/camlp5/Camlp5Helpers.ml
index 575a69de..f084e5aa 100644
--- a/camlp5/Camlp5Helpers.ml
+++ b/camlp5/Camlp5Helpers.ml
@@ -39,7 +39,7 @@ let loc_from_caml camlloc =
 let noloc = Ploc.dummy
 
 type type_arg = MLast.type_var
-let named_type_arg ~loc s : type_arg = (Ploc.VaVal (Some s), (None, false))
+let named_type_arg ~loc s : type_arg = (Ploc.VaVal (Some s), Ploc.VaVal "")
 
 type lab_decl = (loc * string * bool * ctyp)
 let lab_decl ~loc name is_mut typ = (loc, name, is_mut, typ)
@@ -270,7 +270,7 @@ module Typ = struct
   let ident ~loc s = <:ctyp< $lid:s$ >>
   let string ~loc = <:ctyp< string >>
   let unit ~loc = <:ctyp< unit >>
-  let pair ~loc l r = <:ctyp< ( $list:[l;r]$ ) >>
+
 
   let access2 ~loc mname tname =
     assert (HelpersBase.Char.is_uppercase mname.[0]);
@@ -282,7 +282,8 @@ module Typ = struct
   let alias ~loc t s =
     let p = var ~loc s in
     <:ctyp< $t$ as $p$ >>
-  let tuple ~loc lt = <:ctyp< ( $list:lt$ ) >>
+  let tuple ~loc lt = <:ctyp< ( $list:List.map (fun x -> (VaVal None,x)) lt$ ) >>
+  let pair ~loc : t -> t -> t = fun l r -> <:ctyp< ( $list:[(VaVal None, l); (VaVal None, r)]$ ) >>
   let constr ~loc lident =
     let init = of_longident ~loc lident in
     function
@@ -322,7 +323,7 @@ module Typ = struct
       | Ptyp_var s -> <:ctyp< '$s$ >>
       | Ptyp_arrow (lab, l, r) -> arrow ~loc (helper l) (helper r)
       | Ptyp_constr ({txt;_}, ts) -> constr ~loc txt (List.map helper ts)
-      | Ptyp_tuple ts -> <:ctyp< ( $list:(List.map helper ts)$ ) >>
+      | Ptyp_tuple ts -> <:ctyp< ( $list:(List.map (fun x -> (Ploc.VaVal None, helper x)) ts)$ ) >>
       | Ptyp_variant (cs, flg, None) ->
           variant ~loc ~is_open:(match flg with Closed -> false | Open -> true) cs
       | Ptyp_variant (_,_,Some _ )
@@ -436,7 +437,7 @@ module Str = struct
     <:str_item< class $list:[c]$ >>
 
   let tdecl ~loc ~name ~params rhs =
-    let tdPrm = List.map (fun s -> (VaVal (Some s), (None,false))) params in
+    let tdPrm = List.map (fun s -> (VaVal (Some s), VaVal "")) params in
     let t = <:type_decl< $tp:(loc, VaVal name)$ $list:tdPrm$ = $rhs$ >>
     in
     <:str_item< type $list:[t]$ >>
@@ -454,7 +455,7 @@ module Str = struct
     fun ~loc ~name ~params_count ts ->
     let ltv =
       List.init params_count (fun n ->
-          (VaVal (Some (Printf.sprintf "dummy%d" n)), (None, false))) in
+          (VaVal (Some (Printf.sprintf "dummy%d" n)), VaVal "")) in
     let ls = (loc, VaVal name) in
     let ltt = [] in
     let t =
@@ -595,7 +596,7 @@ module Sig = struct
       <:ctyp< [ $list:cs$ ] >>
     in
     let tdPrm = List.init params_count (fun n ->
-            (VaVal (Some (Printf.sprintf "dummy%d" n)), (None,false))) in
+            (VaVal (Some (Printf.sprintf "dummy%d" n)), VaVal "")) in
     let td = <:type_decl< $tp:(loc, VaVal name)$ $list:tdPrm$ = $tdDef$ >>
     in
     <:sig_item< type $list:[td]$ >>
@@ -604,7 +605,7 @@ module Sig = struct
 
   let tdecl_abstr: loc:loc -> string -> string option list -> t = fun ~loc name params ->
 
-    let tdPrm = List.map (fun s -> (VaVal s, (None,false))) params in
+    let tdPrm = List.map (fun s -> (VaVal s, VaVal "")) params in
     let td = <:type_decl< $tp:(loc, VaVal name)$ $list:tdPrm$ = 'abstract >>
     in
     <:sig_item< type $list:[td]$ >>
@@ -779,7 +780,8 @@ let typ_vars_of_typ t =
     | <:ctyp< { $list:llsbt$ } >>  ->
       ListLabels.fold_left ~init:acc ~f:(fun acc (_,_,_,t, _) -> helper acc t) llsbt
     | <:ctyp< [ $list:llslt$ ] >> -> failwith "sum"
-    | <:ctyp< ( $list:lt$ )    >> -> ListLabels.fold_left ~init:acc ~f:helper lt
+    | <:ctyp< ( $list:lt$ )    >> ->
+      ListLabels.fold_left ~init:acc ~f:(fun acc (_,x) -> helper acc x) lt
     | <:ctyp< [ = $list:lpv$ ] >>  -> failwith "polyvariant"
     | _ -> acc (* This could be wrong *)
   in
diff --git a/dune-project b/dune-project
index 5648ccbe..68d154b1 100644
--- a/dune-project
+++ b/dune-project
@@ -24,7 +24,7 @@
   "Yet another library for generic programming. Provides syntax extensions\nboth for camlp5 and PPX which allow decoration of type declarations with\nfollowing compile-time code generation. Provides the way for creating\nplugins (compiled separately from the library) for enchancing supported\ntype transformations.\n\nStrongly reminds the `visitors` library from François Pottier.\nDuring desing of a library of these kind there many possible\ndesign decision and in many cases we decided to implement\nthe decision opposite to the one used in `visitors`.\n\n\nP.S. Since 2023 development team is no longer associated with JetBrains Research")
  (authors "https://github.com/dboulytchev" "https://github.com/Kakadu")
  (maintainers "Kakadu@pm.me")
- (version 0.5.3)
+ (version 0.5.5)
  (depends
   (ocaml
    (or
@@ -33,12 +33,12 @@
      (< "5.0.0"))
     (and
      (>= "5.2.0")
-     (< "5.3.0"))))
+     (<= "5.4.0"))))
   dune
   (ppxlib
    (<= "0.34.0"))
   (camlp5
-   (>= "8.00.05"))
+   (>= "8.04.00"))
   ocamlgraph
   ppx_inline_test_nobase
   (mdx :build)
@@ -56,10 +56,10 @@
  (name GT-bench)
  (synopsis "Some benchmarks. Should not be installed")
  (version 0.1)
+ (allow_empty)
  (authors "Dmitrii Kosarev a.k.a. Kakadu")
  (maintainers "Kakadu@pm.me")
  (depends
   dune
   (benchmark
    (< "1.7"))))
-