diff --git a/check/src/io.cppo.ml b/check/src/io.cppo.ml
index a78ee2c..7390a21 100644
--- a/check/src/io.cppo.ml
+++ b/check/src/io.cppo.ml
@@ -9,12 +9,12 @@ let isatty fd =
   #endscope
 
 
-#if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 1, 0)
+#if OCAML_VERSION >= (5, 1, 0)
+let input_lines = In_channel.input_lines
+#else
 let [@tail_mod_cons] rec input_lines ic =
   (* reproduce https://github.com/ocaml/ocaml/blob/5.3.0/stdlib/in_channel.ml#L195 *)
   match In_channel.input_line ic with
   | Some line -> line :: input_lines ic
   | None -> []
-#elif OCAML_VERSION >= (5, 1, 0) && OCAML_VERSION < (5, 6, 0)
-let input_lines = In_channel.input_lines
 #endif
diff --git a/src/deadArg.ml b/src/deadArg.ml
index 0219b2d..f99b259 100644
--- a/src/deadArg.ml
+++ b/src/deadArg.ml
@@ -70,22 +70,6 @@ let deferrable_register_use label expr builddir loc last_loc count_tbl =
     else register_use ()
   else register_use ()
 
-let options_of_args args =
-  #if OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-  (* Texp_apply's args changed in OCaml 5.4, from expression option
-     to arg_or_omitted. This does the reverse conversion *)
-  let args =
-    List.map
-      (fun (lab, arg) ->
-        match arg with
-        | Arg expr -> lab, Some expr
-        | Omitted _ -> lab, None
-      )
-      args
-  in
-  #endif
-  args
-
 let rec register_uses builddir loc args =
   List.iter
     (fun (_, e) -> Option.iter (register_higher_order_uses builddir) e)
@@ -148,10 +132,10 @@ and register_higher_order_uses builddir e =
       in
       let$ (c_lhs, c_rhs) =
         match expr.exp_desc with
-        #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-        | Texp_function {cases = [case]; _} ->
-        #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
+        #if OCAML_VERSION >= (5, 2, 0)
         | Texp_function (_, Tfunction_cases {cases = [case]; _}) ->
+        #else
+        | Texp_function {cases = [case]; _} ->
         #endif
             Some (case.c_lhs, case.c_rhs)
         | _ -> None
@@ -161,7 +145,7 @@ and register_higher_order_uses builddir e =
           if c_lhs.pat_loc.loc_ghost && c_rhs.exp_loc.loc_ghost
              && expr.exp_loc.loc_ghost
           then
-            let args = options_of_args args in
+            let args = Utils.Compat.options_of_args args in
             register_uses builddir ident_loc args
       | _ -> ()
     )
@@ -178,7 +162,9 @@ let register_uses val_loc args =
 let rec bind loc expr =
   let state = State.get_current () in
   match expr.exp_desc with
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
+  #if OCAML_VERSION >= (5, 2, 0)
+  | Texp_function (params, body) -> bind_function loc params body
+  #else
   | Texp_function {arg_label; cases; _} ->
       let expr_loc = expr.exp_loc.Location.loc_start in
       bind_function loc expr_loc arg_label cases
@@ -203,9 +189,6 @@ let rec bind loc expr =
           expr.exp_attributes
       in
       if is_default expr then bind loc in_expr
-  #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
-  | Texp_function (params, body) ->
-      bind_function loc params body
   #endif
   | exp_desc
     when Config.must_report_opt_args state.config
@@ -222,34 +205,26 @@ let rec bind loc expr =
       VdNode.merge_locs loc loc2
   | _ -> ()
 
-and bind_function loc =
+and register_optional_param state loc = function
+  | Asttypes.Optional s
+    when Config.must_report_opt_args state.State.config ->
+      let (opts, next) = VdNode.get loc in
+      VdNode.update loc (s :: opts, next)
+  | _ -> ()
+
+and arg_type arg_label pat_type =
+  match arg_label with
+  | Asttypes.Optional _ ->
+      (* The type of optional arguments is wrapped in option *)
+      begin match get_deep_desc pat_type with
+      | Tconstr (_, [typ], _) -> typ
+      | _ -> pat_type
+      end
+  | _ -> pat_type
+
+#if OCAML_VERSION >= (5, 2, 0)
+and bind_function loc params body =
   let state = State.get_current () in
-  let register_optional_param = function
-    | Asttypes.Optional s
-      when Config.must_report_opt_args state.config ->
-        let (opts, next) = VdNode.get loc in
-        VdNode.update loc (s :: opts, next)
-    | _ -> ()
-  in
-  let arg_type arg_label pat_type =
-    match arg_label with
-    | Asttypes.Optional _ ->
-        (* The type of optional arguments is wrapped in option *)
-        begin match get_deep_desc pat_type with
-        | Tconstr (_, [typ], _) -> typ
-        | _ -> pat_type
-        end
-    | _ -> pat_type
-  in
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-  fun expr_loc arg_label -> function
-    | {c_lhs = {pat_type; _}; c_rhs; _}::[] ->
-        let arg_type = arg_type arg_label pat_type in
-        DeadType.check_style arg_type expr_loc;
-        register_optional_param arg_label;
-        bind loc c_rhs
-    | _ -> ()
-  #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
   let process_params params =
     let check_param_style arg_loc arg_label = function
       | Tparam_pat {pat_type; _}
@@ -260,7 +235,7 @@ and bind_function loc =
     List.iter
       (fun {fp_kind; fp_arg_label; fp_loc; _} ->
         check_param_style fp_loc fp_arg_label fp_kind;
-        register_optional_param fp_arg_label
+        register_optional_param state loc fp_arg_label
       )
       params
   in
@@ -270,10 +245,21 @@ and bind_function loc =
         bind loc exp
     | _ -> ()
   in
-  fun params body ->
-    process_params params;
-    process_body body
-  #endif
+  process_params params;
+  process_body body
+#elif OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
+and bind_function loc expr_loc arg_label cases =
+  let state = State.get_current () in
+    match cases with
+    | {c_lhs = {pat_type; _}; c_rhs; _}::[] ->
+        let arg_type = arg_type arg_label pat_type in
+        DeadType.check_style arg_type expr_loc;
+        register_optional_param state loc arg_label;
+        bind loc c_rhs
+    | _ -> ()
+#else
+#error "unsupported version"
+#endif
 
                 (********   WRAPPING  ********)
 
diff --git a/src/deadArg.mli b/src/deadArg.mli
index 23e7543..c7c7a9b 100644
--- a/src/deadArg.mli
+++ b/src/deadArg.mli
@@ -27,18 +27,6 @@ val eocb : unit -> unit
     locations, their respective files.
     [eocb] = end of code base. *)
 
-val options_of_args :
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 4, 0)
-  (Asttypes.arg_label * expression option) list
-  #elif OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-  (Asttypes.arg_label * (expression, unit) arg_or_omitted) list
-  #endif
-  -> (Asttypes.arg_label * expression option) list
-(** Convert Texp_apply's args representation to its OCaml 5.3 representation.
-    In particular, the type of a single arg changed in OCaml 5.4, from
-    expression option to arg_or_omitted. This does the reverse conversion.
-*)
-
 val register_uses :
   Lexing.position -> (Asttypes.arg_label * expression option) list -> unit
 (** An optional argument is used if it is required match a signature, or if it
diff --git a/src/deadCode.ml b/src/deadCode.ml
index 73095ba..0b5cecf 100644
--- a/src/deadCode.ml
+++ b/src/deadCode.ml
@@ -35,19 +35,15 @@ let main_files = Hashtbl.create 256   (* names -> paths *)
 let rec treat_exp exp args =
   match exp.exp_desc with
   | Texp_apply (exp, in_args) ->
-      let in_args = DeadArg.options_of_args in_args in
+      let in_args = Utils.Compat.options_of_args in_args in
       treat_exp exp (in_args @ args)
 
   | Texp_ident (_, _, {Types.val_loc = {Location.loc_start = loc; _}; _})
   | Texp_field (_, _, {lbl_loc = {Location.loc_start = loc; _}; _}) ->
       DeadArg.register_uses loc args
 
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
-  | Texp_match (_, comp_l, _) ->
-    let val_l = [] in (* effect cases appear in OCaml 5.3 *)
-  #elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
-  | Texp_match (_, comp_l, val_l, _) ->
-  #endif
+  | Texp_match _ as exp_desc ->
+      let (_, comp_l, val_l, _) = Utils.Compat.get_match_data_exn exp_desc in
       let process_cases l =
         List.iter (fun {c_rhs = exp; _} -> treat_exp exp args) l
       in
@@ -68,24 +64,18 @@ let value_binding super self x =
   let at_eof_saved = !DeadArg.at_eof in
   DeadArg.at_eof := [];
   incr depth;
-  let open Asttypes in
-  begin match x.vb_pat.pat_desc with
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-  | Tpat_var (_, {loc; _})
-  #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
-  | Tpat_var (_, {loc; _}, _)
-  #endif
-    when not loc.Location.loc_ghost ->
-      let loc = loc.Location.loc_start in
+  begin match Utils.Compat.get_var_data x.vb_pat.pat_desc with
+  | Ok (_, {loc=pat_loc; _}, _) when not pat_loc.Location.loc_ghost ->
+      let pat_loc = pat_loc.Location.loc_start in
       begin match x.vb_expr.exp_desc with
       | Texp_ident (_, _, {val_loc; _}) when not val_loc.Location.loc_ghost ->
           let val_loc = val_loc.Location.loc_start in
-          VdNode.merge_locs loc val_loc;
-          DeadObj.add_equal loc val_loc
+          VdNode.merge_locs pat_loc val_loc;
+          DeadObj.add_equal pat_loc val_loc
       | _ ->
           let exp = x.vb_expr in
-          DeadArg.bind loc exp;
-          DeadObj.add_var loc exp
+          DeadArg.bind pat_loc exp;
+          DeadObj.add_var pat_loc exp
       end
   | _ -> ()
   end;
@@ -125,25 +115,12 @@ let structure_item super self i =
   r
 
 
-let id_of_var : type k . k pattern_desc -> Ident.t option = function
+let id_of_var pat_desc =
   (* helper function to extract the var's id in  tpat_var and
      tpat_alias(tpat_any) patterns for all OCaml versions *)
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-  | Tpat_var (id, _)
-  #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
-  | Tpat_var (id, _, _)
-  #endif
-    (* x *)
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-  | Tpat_alias ({pat_desc=Tpat_any; _}, id, _)
-  #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 4, 0)
-  | Tpat_alias ({pat_desc=Tpat_any; _}, id, _, _)
-  #elif OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-  | Tpat_alias ({pat_desc=Tpat_any; _}, id, _, _, _)
-  #endif
-    (* (x: t) *)
-    -> Some id
-  | _ -> None
+  Utils.Compat.get_var_data pat_desc
+  |> Result.to_option
+  |> Option.map (fun (id, _, _) -> id)
 
 
 let pat: type k. Tast_mapper.mapper -> Tast_mapper.mapper -> k general_pattern -> k general_pattern =
@@ -154,16 +131,9 @@ let pat: type k. Tast_mapper.mapper -> Tast_mapper.mapper -> k general_pattern -
   let u s =
     register_style pat_loc (Printf.sprintf "unit pattern %s" s)
   in
-  let open Asttypes in
   if DeadType.is_unit p.pat_type && sections.style.unit_pat then begin
     match p.pat_desc with
       | Tpat_construct _ -> ()
-      #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-      | Tpat_var (_, {txt = "eta"; _})
-      #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
-      | Tpat_var (_, {txt = "eta"; _}, _)
-      #endif
-        when p.pat_loc = Location.none -> ()
       | Tpat_any -> if state.config.underscore then u "_"
       | Tpat_value tpat_arg ->
         begin match (tpat_arg :> value general_pattern) with
@@ -171,21 +141,22 @@ let pat: type k. Tast_mapper.mapper -> Tast_mapper.mapper -> k general_pattern -
         | _ -> u "!!pattern!!"
         end
       | var ->
-          match id_of_var var with
+        match id_of_var var with
           | Some id ->
               let txt = Ident.name id in
-              if check_underscore txt then u txt
+              if txt = "eta" && p.pat_loc = Location.none then ()
+              else if check_underscore txt then u txt
           | None -> u "!!pattern!!"
   end;
   begin match p.pat_desc with
   | Tpat_record (l, _) ->
       List.iter
         (fun (_, lab, _) ->
-          #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 4, 0)
-          let lab : Types.label_description = lab in
-          #elif OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
+          #if OCAML_VERSION >= (5, 4, 0)
           (* The type of lab moved in OCaml 5.4 *)
           let lab : Data_types.label_description = lab in
+          #else
+          let lab : Types.label_description = lab in
           #endif
           let lab_loc = lab.lbl_loc.Location.loc_start in
           if exported ~is_type:true sections.types lab_loc then
@@ -229,7 +200,7 @@ let expr super self e =
 
 
   | Texp_apply (exp, args) ->
-      let args = DeadArg.options_of_args args in
+      let args = Utils.Compat.options_of_args args in
       if Config.must_report_opt_args state.config then
         treat_exp exp args;
       begin match exp.exp_desc with
@@ -254,21 +225,19 @@ let expr super self e =
             "let () = ... in ... (=> use sequence)"
       end
 
-  #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
-  | Texp_match (_, [{c_lhs; _}], _)
-  #elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
-  | Texp_match (_, [{c_lhs; _}], [], _)
-  #endif
-    when DeadType.is_unit c_lhs.pat_type && sections.style.seq ->
-      begin match c_lhs.pat_desc with
-      | Tpat_value tpat_arg ->
-        begin match (tpat_arg :> value general_pattern) with
-        | {pat_desc=Tpat_construct _; _} ->
-            register_style
-              c_lhs.pat_loc.Location.loc_start
-              "let () = ... in ... (=> use sequence)"
-        | _ -> ()
-        end
+  | Texp_match _ as exp_desc when sections.style.seq ->
+      let (_, comp_l, val_l, _) = Utils.Compat.get_match_data_exn exp_desc in
+      begin match comp_l, val_l with
+      | {c_lhs={pat_desc=Tpat_value v_pat; _} as c_lhs; _}::[], []
+        when DeadType.is_unit c_lhs.pat_type ->
+          (* split pattern matching for type checking *)
+          begin match (v_pat :> value general_pattern) with
+          | {pat_desc=Tpat_construct _; _} ->
+              register_style
+                c_lhs.pat_loc.Location.loc_start
+                "let () = ... in ... (=> use sequence)"
+          | _ -> ()
+          end
       | _ -> ()
       end
 
diff --git a/src/deadLexiFi.ml b/src/deadLexiFi.ml
index 6f8ff48..4c16038 100644
--- a/src/deadLexiFi.ml
+++ b/src/deadLexiFi.ml
@@ -47,14 +47,16 @@ module Extension = struct
 
   let sig_value (value : Types.value_description) =
     let add strct = match strct.pstr_desc with
-      #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
-      | Pstr_eval ({pexp_desc = Pexp_constant (Pconst_string (s, _, _));
-                    _}, _) ->
-      #elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
-      | Pstr_eval ({pexp_desc = Pexp_constant {pconst_desc= (Pconst_string (s, _, _)); _};
-                    _}, _) ->
-      #endif
-          hashtbl_add_unique_to_list str s value.val_loc.loc_start
+      | Pstr_eval ({pexp_desc; _}, _) ->
+          begin match pexp_desc with
+            #if OCAML_VERSION >= (5, 3, 0)
+            | Pexp_constant {pconst_desc= (Pconst_string (s, _, _)); _} ->
+            #else
+            | Pexp_constant (Pconst_string (s, _, _)) ->
+            #endif
+                hashtbl_add_unique_to_list str s value.val_loc.loc_start
+            | _ -> ()
+          end
       | _ -> ()
     in
     let add = function
@@ -135,11 +137,7 @@ module Extension = struct
       match get_deep_desc typ with
       | Tarrow (_, t, _, _) -> process (p, t, call_site)
       | Ttuple ts ->
-          #if OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-           (* Ttuple's ts' content changed in OCaml 5.4, from type_expr to
-              (string option * type_expr). This does the reverse conversion *)
-          let ts = List.map snd ts in
-          #endif
+          let ts = Utils.Compat.unlabel_tuple ts in
           List.iter (fun t -> process (p, t, call_site)) ts
       | Tconstr (path, ts, _) ->
           let name = Path.name path in
diff --git a/src/deadObj.ml b/src/deadObj.ml
index 0e7e199..b4b9ac3 100644
--- a/src/deadObj.ml
+++ b/src/deadObj.ml
@@ -144,13 +144,12 @@ let rec treat_fields action typ = match get_deep_desc typ with
 
 let rec repr_exp expr f =
   match expr.exp_desc with
+    | Texp_function _ as exp_desc ->
+        begin match Utils.Compat.get_function_bodies exp_desc with
+        | Ok (expr::_) -> repr_exp expr f
+        | _ -> assert false
+        end
     | Texp_sequence (_, expr)
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-    | Texp_function {cases = {c_rhs=expr; _}::_ ; _}
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
-    | Texp_function (_, Tfunction_cases { cases = {c_rhs=expr; _}::_ ; _ })
-    | Texp_function (_, Tfunction_body expr)
-    #endif
     | Texp_let (_, _, expr)
     | Texp_apply (expr, _) -> repr_exp expr f
     | _ -> f expr
@@ -292,17 +291,12 @@ let add_var loc expr =
     | Texp_ident (_, _, {Types.val_loc; _}) ->
         `Ident val_loc.Location.loc_start
     (* Cases not traversed by repr_exp *)
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
-    | Texp_match (_, cases, _) ->
+    | Texp_match _ as exp_desc ->
+        let (_, cases, _, _) = Utils.Compat.get_match_data_exn exp_desc in
         find_first_case_kind cases
-    | Texp_try (_, cases) ->
+    | Texp_try _ as exp_desc ->
+        let (_, cases, _) = Utils.Compat.get_try_data_exn exp_desc in
         find_first_case_kind cases
-    #elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
-    | Texp_match (_, cases, _, _) ->
-        find_first_case_kind cases
-    | Texp_try (_, cases, _) ->
-        find_first_case_kind cases
-    #endif
     | Texp_ifthenelse (_, then_, Some else_) ->
         find_first_kind [then_; else_]
     (* Default *)
@@ -327,15 +321,8 @@ let class_structure cl_struct =
     | Tpat_var _ when not pat.pat_loc.Location.loc_ghost ->
         add_equal pat.pat_loc.Location.loc_start !last_class
     | _ -> () end;
-    match pat.pat_desc with
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-    | Tpat_alias (pat, _, _) ->
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 4, 0)
-    | Tpat_alias (pat, _, _, _) ->
-    #elif OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-    | Tpat_alias (pat, _, _, _, _) ->
-    #endif
-        add_aliases pat
+    match Utils.Compat.get_alias_data pat.pat_desc with
+    | Ok (pat, _, _, _) -> add_aliases pat
     | _ -> ()
   in
   add_aliases cl_struct.cstr_self
diff --git a/src/deadSign.ml b/src/deadSign.ml
index 475cc5e..e870a74 100644
--- a/src/deadSign.ml
+++ b/src/deadSign.ml
@@ -169,29 +169,6 @@ let collect_export_from_structure ~path ~comp_unit structure =
     | Tpat_constant _
     | Tpat_variant (_, None, _) ->
         ()
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-    | Tpat_var (id, {loc; _}) ->
-        let uid = Shape.Uid.internal_not_actually_unique in
-        (* uid appear in OCaml 5.2. Dummy value because we do not rely on it *)
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
-    | Tpat_var (id, {loc; _}, uid) ->
-    #endif
-        let id = Ident.name id in
-        let value = value_of pat loc uid in
-        export export_value ~path id value
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-    | Tpat_alias (sub_pat, id, {loc; _}) ->
-        let uid = Shape.Uid.internal_not_actually_unique in
-        (* uid appear in OCaml 5.2. Dummy value because we do not rely on it *)
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 4, 0)
-    | Tpat_alias (sub_pat, id, {loc; _}, uid) ->
-    #elif OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-    | Tpat_alias (sub_pat, id, {loc; _}, uid, _) ->
-    #endif
-        let id = Ident.name id in
-        let value = value_of pat loc uid in
-        export export_value ~path id value;
-        collect_value ~path sub_pat
     | Tpat_or (pat, _, _)
         (* In [P1 | P2], both branches must define the same names.
            Only the locations of the names in [P1] are used to refer to
@@ -200,21 +177,33 @@ let collect_export_from_structure ~path ~comp_unit structure =
     | Tpat_lazy pat ->
         collect_value ~path pat
     | Tpat_tuple pats ->
-        #if OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
-         (* Tpat_tuple's pats changed in OCaml 5.4, from pat list to
-            (string option * pat) list. This does the reverse conversion *)
-        let pats = List.map snd pats in
-        #endif
+        let pats = Utils.Compat.unlabel_tuple pats in
         List.iter (collect_value ~path) pats
     | Tpat_construct (_, _, pats, _)
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 4, 0)
-    | Tpat_array pats ->
-    #elif OCAML_VERSION >= (5, 4, 0) && OCAML_VERSION < (5, 6, 0)
+    #if OCAML_VERSION >= (5, 4, 0)
     | Tpat_array (_, pats) ->
+    #else
+    | Tpat_array pats ->
     #endif
         List.iter (collect_value ~path) pats
     | Tpat_record (fields, _) ->
         List.iter (fun (_, _, pat) -> collect_value ~path pat) fields
+    | (Tpat_var _ | Tpat_alias _) as pat_desc ->
+        let sub_pat, id, loc, uid =
+          (* similar to Utils.Compat.alias_data but the first field (the
+             aliased pattern) is None for Tpat_var and Some for Tpat_alias *)
+          match Utils.Compat.get_var_data pat_desc with
+          | Ok (id, {loc; _}, uid) -> (None, id, loc, uid)
+          | Error _ ->
+              let (sub_pat, id, loc, uid) =
+                Utils.Compat.get_alias_data_exn pat_desc
+              in
+              (Some sub_pat, id, loc, uid)
+        in
+        let id = Ident.name id in
+        let value = value_of pat loc uid in
+        export export_value ~path id value;
+        Option.iter (collect_value ~path) sub_pat
 
   and collect_module ~path m =
     match m.mod_desc with
@@ -226,7 +215,7 @@ let collect_export_from_structure ~path ~comp_unit structure =
         collect_structure ~path structure
     | Tmod_functor (_, m)
     | Tmod_apply (m, _, _)
-    #if OCAML_VERSION >= (5, 1, 0) && OCAML_VERSION < (5, 6, 0)
+    #if OCAML_VERSION >= (5, 1, 0)
     | Tmod_apply_unit m (* Constructor introduced in OCaml 5.1 *)
     #endif
     | Tmod_constraint (m, _, Tmodtype_implicit, _) ->
@@ -316,7 +305,7 @@ let collect_from_include incl_decl =
         (None, signature)
     | Tmod_functor (_, mod_expr)
     | Tmod_apply (mod_expr, _, _)
-    #if OCAML_VERSION >= (5, 1, 0) && OCAML_VERSION < (5, 6, 0)
+    #if OCAML_VERSION >= (5, 1, 0)
     | Tmod_apply_unit mod_expr (* Constructor introduced in OCaml 5.1 *)
     #endif
     | Tmod_constraint (mod_expr, _, _, _) ->
@@ -426,7 +415,7 @@ let collect_eq_from_module_alias ~path module_binding =
               mt
         | Tmod_constraint (mod_expr, _, _, _)
         | Tmod_functor (_, mod_expr)
-        #if OCAML_VERSION >= (5, 1, 0) && OCAML_VERSION < (5, 6, 0)
+        #if OCAML_VERSION >= (5, 1, 0)
         | Tmod_apply_unit mod_expr (* Constructor introduced in OCaml 5.1 *)
         #endif
         | Tmod_apply (mod_expr, _, _) ->
diff --git a/src/state/file_infos.ml b/src/state/file_infos.ml
index f45a6a4..ce0ace6 100644
--- a/src/state/file_infos.ml
+++ b/src/state/file_infos.ml
@@ -44,10 +44,10 @@ let init_from_all_cm_infos ~cm_file cmt_infos =
   let cm_infos =
     match cmt_infos.cmt_annots with
     | Interface sign ->
-        #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
-        let cmti_uid_to_decl = Location_dependencies.NA in
-        #elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
+        #if OCAML_VERSION >= (5, 3, 0)
         let cmti_uid_to_decl = cmt_infos.cmt_uid_to_decl in
+        #else
+        let cmti_uid_to_decl = Location_dependencies.NA in
         #endif
         Cmti {sign; cmti_uid_to_decl}
     | Implementation strc ->
diff --git a/src/state/location_dependencies.ml b/src/state/location_dependencies.ml
index db268ac..a2fdc60 100644
--- a/src/state/location_dependencies.ml
+++ b/src/state/location_dependencies.ml
@@ -4,20 +4,7 @@ let empty = []
 
 module UidTbl = Shape.Uid.Tbl
 
-#if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
-
-type uid_to_decl = NA
-
-let init ~comp_unit_to_path:_ cmt_infos _cmti_uid_to_decl =
-  match cmt_infos with
-  | Cmt_format.{cmt_annots = Implementation _; cmt_value_dependencies; _} ->
-    let loc_of_vd vd = vd.Types.val_loc.loc_start in
-    cmt_value_dependencies
-    |> List.map (fun (vd1, vd2) -> loc_of_vd vd1, loc_of_vd vd2)
-    |> Result.ok
-  | _ -> Result.error "No implementation found in cmt_infos"
-
-#elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
+#if OCAML_VERSION >= (5, 3, 0)
 (* Since OCaml 5.3, cmt_infos.cmt_value_dependencies is not available.
    We try to reproduce it using the cmti_uid_to_decl and comp_unit_to_path
    information, respectively found in a .cmti's cmt_infos and built using
@@ -42,7 +29,7 @@ let fill_from_cmt_tbl uid_to_decl res_uid_to_loc =
 
 let find_opt_external_uid_loc ~comp_unit_to_path = function
   | Shape.Uid.(Compilation_unit _ | Internal | Predef _) -> None
-  #if OCAML_VERSION >= (5, 5, 0) && OCAML_VERSION < (5, 6, 0)
+  #if OCAML_VERSION >= (5, 5, 0)
   | Local_opaque_item _ -> None
   #endif
   | Item {comp_unit; from; _} as uid ->
@@ -106,4 +93,21 @@ let init ~comp_unit_to_path cmt_infos cmti_uid_to_decl =
     |> Result.ok
   | _ -> Result.error "No implementation found in cmt_infos"
 
+
+#elif OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
+
+type uid_to_decl = NA
+
+let init ~comp_unit_to_path:_ cmt_infos _cmti_uid_to_decl =
+  match cmt_infos with
+  | Cmt_format.{cmt_annots = Implementation _; cmt_value_dependencies; _} ->
+    let loc_of_vd vd = vd.Types.val_loc.loc_start in
+    cmt_value_dependencies
+    |> List.map (fun (vd1, vd2) -> loc_of_vd vd1, loc_of_vd vd2)
+    |> Result.ok
+  | _ -> Result.error "No implementation found in cmt_infos"
+
+
+#else
+#error "unsupported version"
 #endif
diff --git a/src/state/location_dependencies.mli b/src/state/location_dependencies.mli
index bce18d2..d3f2225 100644
--- a/src/state/location_dependencies.mli
+++ b/src/state/location_dependencies.mli
@@ -3,15 +3,15 @@ type t = (Lexing.position * Lexing.position) list
 
 val empty : t (** No signature read *)
 
-#if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
+#if OCAML_VERSION >= (5, 3, 0)
+type uid_to_decl = Typedtree.item_declaration Shape.Uid.Tbl.t
+#else
 (* The corresponding [cmt_infos.cmt_uid_to_decl] is introduced in
    OCaml 5.2 but not used until OCaml 5.3 (see {!init} below).
    We still provide a constructor to keep the state representation as
    uniform as possible.
 *)
 type uid_to_decl = NA
-#elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
-type uid_to_decl = Typedtree.item_declaration Shape.Uid.Tbl.t
 #endif
 
 val init :
diff --git a/src/utils.ml b/src/utils.ml
index 6a4bd76..690fe02 100644
--- a/src/utils.ml
+++ b/src/utils.ml
@@ -10,7 +10,9 @@ module Filepath = struct
     | _ -> filepath
 
   let unit filepath =
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 3, 0)
+    #if OCAML_VERSION >= (5, 3, 0)
+    Unit_info.lax_modname_from_source filepath
+    #else
     (* reproduce https://github.com/ocaml/ocaml/blob/5.3/parsing/unit_info.ml#L60 *)
     let remove_all_ext basename =
       match String.index basename '.' with
@@ -18,8 +20,6 @@ module Filepath = struct
         | exception Not_found -> basename
     in
     filepath |> Filename.basename |> remove_all_ext |> String.capitalize_ascii
-    #elif OCAML_VERSION >= (5, 3, 0) && OCAML_VERSION < (5, 6, 0)
-    Unit_info.lax_modname_from_source filepath
     #endif
 
   type kind =
@@ -38,10 +38,10 @@ module Filepath = struct
     )
     else if Sys.is_directory filepath then Dir
     else if Filename.check_suffix filepath ".cmti" then Cmti
-  else if Filename.check_suffix filepath ".cmt" then
-    let cmti = Filename.remove_extension filepath ^ ".cmti" in
-    if Sys.file_exists cmti then Cmt_with_mli
-    else Cmt_without_mli
+    else if Filename.check_suffix filepath ".cmt" then
+      let cmti = Filename.remove_extension filepath ^ ".cmti" in
+      if Sys.file_exists cmti then Cmt_with_mli
+      else Cmt_without_mli
     else Ignore
 end
 
@@ -72,23 +72,23 @@ module Envaux = struct
   let force_setup () = Lazy.force !setup
 
   type paths =
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-    string list
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
+    #if OCAML_VERSION >= (5, 2, 0)
     Load_path.paths
+    #else
+    string list
     #endif
 
   let init_load_path paths =
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 0, 0)
-    Load_path.init paths
-    #elif OCAML_VERSION >= (5, 0, 0) && OCAML_VERSION < (5, 2, 0)
-    let auto_include = Load_path.no_auto_include in
-    Load_path.init ~auto_include paths
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
+    #if OCAML_VERSION >= (5, 2, 0)
     let auto_include = Load_path.no_auto_include in
     let visible = paths.Load_path.visible in
     let hidden = paths.Load_path.hidden in
     Load_path.init ~auto_include ~visible ~hidden
+    #elif OCAML_VERSION >= (5, 0, 0)
+    let auto_include = Load_path.no_auto_include in
+    Load_path.init ~auto_include paths
+    #else
+    Load_path.init paths
     #endif
 
   let set_loadpaths paths =
@@ -102,3 +102,157 @@ module Envaux = struct
     force_setup ();
     Envaux.env_of_only_summary env
 end
+
+module Compat = struct
+
+  open Typedtree
+
+  (* Conversions *)
+
+  let unlabel_tuple fields =
+    #if OCAML_VERSION >= (5, 4, 0)
+    List.map snd fields
+    #else
+    fields
+    #endif
+
+  let options_of_args args =
+    #if OCAML_VERSION >= (5, 4, 0)
+    (* Texp_apply's args changed in OCaml 5.4, from expression option
+       to arg_or_omitted. This does the reverse conversion *)
+    let args =
+      List.map
+        (fun (lab, arg) ->
+          match arg with
+          | Arg expr -> lab, Some expr
+          | Omitted _ -> lab, None
+        )
+        args
+    in
+    #endif
+    args
+
+  (* Getters *)
+
+  type _ invalid_arg =
+    | Unexpected_pattern : string * 'k pattern_desc -> 'k pattern_desc invalid_arg
+    | Unexpected_expression :
+        string * expression_desc -> expression_desc invalid_arg
+
+  #if OCAML_VERSION < (5, 2, 0)
+  let dummy_uid = Shape.Uid.internal_not_actually_unique
+    (* A uid field appears in multiple constructors in OCaml 5.2.
+       This dummy value serves as replacement. We do not rely on its value
+       but need it to exist for typing. *)
+  #endif
+
+  type ('k, 'a) pat_getter = 'k pattern_desc -> ('a, 'k pattern_desc invalid_arg) result
+
+  type alias_data = value general_pattern * Ident.t * Location.t * Shape.Uid.t
+
+  let get_alias_data : type k . (k, alias_data) pat_getter = function
+    #if OCAML_VERSION >= (5, 4, 0)
+    | Tpat_alias (pat, id, {loc; _}, uid, _) ->
+    #elif OCAML_VERSION >= (5, 2, 0)
+    | Tpat_alias (pat, id, {loc; _}, uid) ->
+    #else
+    | Tpat_alias (pat, id, {loc; _}) ->
+        let uid = dummy_uid in
+    #endif
+      Result.Ok (pat, id, loc, uid)
+    | pat_desc ->
+        let msg = "get_alias_data expects a Tpat_alias" in
+        let err = Unexpected_pattern (msg, pat_desc) in
+        Result.Error err
+
+  let get_alias_data_exn pat_desc =
+    get_alias_data pat_desc |> Result.get_ok
+
+  type var_data = Ident.t * string Location.loc * Shape.Uid.t
+
+  let get_var_data : type k . (k, var_data) pat_getter = function
+    (* x *)
+    #if OCAML_VERSION >= (5, 2, 0)
+    | Tpat_var (id, loc, uid) ->
+    #else
+    | Tpat_var (id, loc) ->
+        let uid = dummy_uid in
+    #endif
+        Result.ok (id, loc, uid)
+    (* (x: t) *)
+    #if OCAML_VERSION >= (5, 4, 0)
+    | Tpat_alias ({pat_desc=Tpat_any; _}, id, loc, uid, _) ->
+    #elif OCAML_VERSION >= (5, 2, 0)
+    | Tpat_alias ({pat_desc=Tpat_any; _}, id, loc, uid) ->
+    #else
+    | Tpat_alias ({pat_desc=Tpat_any; _}, id, loc) ->
+        let uid = dummy_uid in
+    #endif
+        Result.ok (id, loc, uid)
+    | pat_desc ->
+        let msg = "get_var_data expects a Tpat_var or Tpat_alias(Tpat_any)" in
+        let err = Unexpected_pattern (msg, pat_desc) in
+        Result.Error err
+
+  let get_var_data_exn pat_desc =
+    get_var_data pat_desc |> Result.get_ok
+
+  type 'a exp_getter =
+    expression_desc -> ('a, expression_desc invalid_arg) result
+
+  type match_data =
+    expression * computation case list * value case list * partial
+
+  let get_match_data = function
+    #if OCAML_VERSION >= (5, 3, 0)
+    | Texp_match (exp, reg_cases, eff_cases, partial) ->
+    #else
+    | Texp_match (exp, reg_cases, partial) ->
+        let eff_cases = [] in (* effect cases appear in OCaml 5.3 *)
+    #endif
+        Result.Ok (exp, reg_cases, eff_cases, partial)
+    | exp_desc ->
+        let msg = "get_match_data expects a Texp_match" in
+        let err = Unexpected_expression (msg, exp_desc) in
+        Result.Error err
+
+  let get_match_data_exn exp_desc =
+    get_match_data exp_desc |> Result.get_ok
+
+  type try_data =
+    expression * value case list * value case list
+
+  let get_try_data = function
+    #if OCAML_VERSION >= (5, 3, 0)
+    | Texp_try (exp, reg_cases, eff_cases) ->
+    #else
+    | Texp_try (exp, reg_cases) ->
+        let eff_cases = [] in (* effect cases appear in OCaml 5.3 *)
+    #endif
+        Result.Ok (exp, reg_cases, eff_cases)
+    | exp_desc ->
+        let msg = "get_try_data expects a Texp_try" in
+        let err = Unexpected_expression (msg, exp_desc) in
+        Result.Error err
+
+  let get_try_data_exn exp_desc =
+    get_try_data exp_desc |> Result.get_ok
+
+  type function_bodies = expression list
+
+  let get_function_bodies = function
+    #if OCAML_VERSION >= (5, 2, 0)
+    | Texp_function (_, Tfunction_body expr) ->
+        Result.ok [expr]
+    | Texp_function (_, Tfunction_cases { cases ; _ }) ->
+    #else
+    | Texp_function {cases ; _} ->
+    #endif
+        let bodies = List.map (fun {c_rhs; _} -> c_rhs) cases in
+        Result.ok bodies
+    | exp_desc ->
+        let msg = "get_function_bodies expects a Texp_function" in
+        let err = Unexpected_expression (msg, exp_desc) in
+        Result.Error err
+
+end
diff --git a/src/utils.mli b/src/utils.mli
index e5d20e4..883691c 100644
--- a/src/utils.mli
+++ b/src/utils.mli
@@ -43,10 +43,10 @@ module StringSet : Set.S with type elt = String.t
 
 module Envaux : sig
   type paths =
-    #if OCAML_VERSION >= (4, 14, 0) && OCAML_VERSION < (5, 2, 0)
-    string list
-    #elif OCAML_VERSION >= (5, 2, 0) && OCAML_VERSION < (5, 6, 0)
+    #if OCAML_VERSION >= (5, 2, 0)
     Load_path.paths
+    #else
+    string list
     #endif
 
   val set_loadpaths : paths -> unit
@@ -57,3 +57,103 @@ module Envaux : sig
   (** Same as Envaux.env_of_only_summary but ensures the paths submitted
       in set_loadpaths are actually set. *)
 end
+
+module Compat : sig
+
+  open Typedtree
+
+  #if OCAML_VERSION >= (5, 4, 0)
+  val unlabel_tuple : ('a * 'b) list -> 'b list
+  #else
+  val unlabel_tuple : 'a list -> 'a list
+  #endif
+    (** Tuple's field representation changed in OCaml 5.4, with the
+        introduction of labelled tuples. This converts a tuple's fields back
+        into the pre-5.4 representation. *)
+
+val options_of_args :
+  #if OCAML_VERSION >= (5, 4, 0)
+  (Asttypes.arg_label * (expression, unit) arg_or_omitted) list
+  #else
+  (Asttypes.arg_label * expression option) list
+  #endif
+  -> (Asttypes.arg_label * expression option) list
+    (** Apply's arguments representation changed in OCaml 5.4, from
+        expression option to arg_or_omitted. This does the reverse conversion *)
+
+  type _ invalid_arg =
+    | Unexpected_pattern : string * 'k pattern_desc -> 'k pattern_desc invalid_arg
+        (** Used by pattern_desc getters *)
+    | Unexpected_expression :
+        string * expression_desc -> expression_desc invalid_arg
+        (** Used by expression_desc getters *)
+
+  type ('k, 'a) pat_getter = 'k pattern_desc -> ('a, 'k pattern_desc invalid_arg) result
+
+  type alias_data = value general_pattern * Ident.t * Location.t * Shape.Uid.t
+
+  val get_alias_data : 'k . ('k, alias_data) pat_getter
+    (** [get_alias_data pat] expects a [Tpat_alias].
+        It returns [Error Unexpected_pattern] otherwise.
+        It extracts the different components of Tpat_alias.
+        If OCaml < 5.2, the [Uid.t] field is a dummy value.
+        If OCaml >= 5.4, the last field of Tpat_alias is discarded.
+    *)
+
+  val get_alias_data_exn : 'k . 'k pattern_desc -> alias_data
+    (** same as [get_alias_data] but raises instead of returning an Error *)
+
+  type var_data = Ident.t * string Location.loc * Shape.Uid.t
+
+  val get_var_data : 'k . ('k, var_data) pat_getter
+    (** [get_var_data pat] expects a [Tpat_var] or a [Tpat_alias(Tpat_any)].
+        It returns [Error Unexpected_pattern] otherwise.
+        It extracts the different components of Tpat_var.
+        If OCaml < 5.2, the [Uid.t] field is a dummy value.
+        [Tpat_alias(Tpat_any)] is considered equivalent to a [Tpat_var]
+        because in OCaml < 5.5, constrained vars ([x : t]) are translated
+        in this pattern.
+    *)
+
+  val get_var_data_exn : 'k . 'k pattern_desc -> var_data
+    (** same as [get_var_data] but raises instead of returning an Error *)
+
+  type 'a exp_getter =
+    expression_desc -> ('a, expression_desc invalid_arg) result
+
+  type match_data =
+    expression * computation case list * value case list * partial
+
+  val get_match_data : match_data exp_getter
+    (** [get_match_data exp] expects a [Texp_match].
+        It returns [Error Unexpected_expression] otherwise.
+        Otherwise it extracts the different components of Texp_match.
+        If OCaml < 5.3, the [value case list] field is en empty list.
+    *)
+
+  val get_match_data_exn : expression_desc -> match_data
+    (** same as [get_match_data] but raises instead of returning an Error *)
+
+  type try_data = expression * value case list * value case list
+
+  val get_try_data : try_data exp_getter
+    (** [get_try_data exp] expects a [Texp_try].
+        It returns [Error Unexpected_expression] otherwise.
+        Otherwise it extracts the different components of Texp_try.
+        If OCaml < 5.3, the second [value case list] field is en empty list.
+    *)
+
+  val get_try_data_exn : expression_desc -> try_data
+    (** same as [get_try_data] but raises instead of returning an Error *)
+
+  type function_bodies = expression list
+
+  val get_function_bodies : function_bodies exp_getter
+    (** [get_function_bodies exp] expects a [Texp_function].
+        It returns [Error Unexpected_expression] otherwise.
+        Otherwise it returns the expression of the function body.
+        If there are multiple cases, then the returned list contains all the
+        alternative expressions.
+    *)
+
+end