diff --git a/src/lib/uTop.ml b/src/lib/uTop.ml
index ad717d8..926e740 100644
--- a/src/lib/uTop.ml
+++ b/src/lib/uTop.ml
@@ -342,7 +342,13 @@ let check_phrase phrase =
             (fun () ->
                Str.eval
                  (Exp.fun_ nolabel None (Pat.construct unit None)
-                   (Exp.letmodule (with_loc loc "_")
+                   (Exp.letmodule (with_loc loc
+                        #if OCAML_VERSION >= (4, 10, 0)
+                        (Some "_")
+                        #else
+                          "_"
+                        #endif
+                        )
                       (Mod.structure (item :: items))
                       (Exp.construct unit None))))
         in
diff --git a/src/lib/uTop_complete.ml b/src/lib/uTop_complete.ml
index 86b7b39..131308e 100644
--- a/src/lib/uTop_complete.ml
+++ b/src/lib/uTop_complete.ml
@@ -516,8 +516,14 @@ let rec fields_of_module_type = function
       String_set.empty
 
 let lookup_module id env =
+#if OCAML_VERSION >= (4, 10, 0)
+  let path, decl = Env.find_module_by_name id env in
+  (path, decl.md_type)
+#else
   let path = Env.lookup_module id env ~load:true in
   (path, (Env.find_module path env).md_type)
+#endif
+
 let find_module path env = (Env.find_module path env).md_type
 
 let names_of_module longident =
@@ -551,6 +557,10 @@ let fields_of_module longident =
 let list_global_names () =
   let rec loop acc = function
     | Env.Env_empty -> acc
+#if OCAML_VERSION >= (4, 10, 0)
+    | Env.Env_value_unbound _-> acc
+    | Env.Env_module_unbound _-> acc
+#endif
     | Env.Env_value(summary, id, _) ->
         loop (add (Ident.name id) acc) summary
     | Env.Env_type(summary, id, decl) ->
@@ -579,8 +589,8 @@ let list_global_names () =
     | Env.Env_constraints (summary, _) ->
         loop acc summary
 #endif
-#if OCAML_VERSION >= (4, 08, 0)
-    | Env.Env_copy_types (summary, _) ->
+#if OCAML_VERSION >= (4, 10, 0)
+    | Env.Env_copy_types summary ->
         loop acc summary
 #else
 #if OCAML_VERSION >= (4, 06, 0)
@@ -626,6 +636,10 @@ let replace x y set =
 let list_global_fields () =
   let rec loop acc = function
     | Env.Env_empty -> acc
+#if OCAML_VERSION >= (4, 10, 0)
+    | Env.Env_value_unbound _-> acc
+    | Env.Env_module_unbound _-> acc
+#endif
     | Env.Env_value(summary, id, _) ->
         loop (add (Ident.name id) acc) summary
     | Env.Env_type(summary, id, decl) ->
@@ -654,9 +668,14 @@ let list_global_fields () =
     | Env.Env_constraints (summary, _) ->
         loop acc summary
 #endif
-#if OCAML_VERSION >= (4, 06, 0)
-    | Env.Env_copy_types (summary, _) ->
+#if OCAML_VERSION >= (4, 10, 0)
+    | Env.Env_copy_types summary ->
         loop acc summary
+#else
+  #if OCAML_VERSION >= (4, 06, 0)
+      | Env.Env_copy_types (summary, _) ->
+          loop acc summary
+  #endif
 #endif
 #if OCAML_VERSION >= (4, 07, 0)
   #if OCAML_VERSION >= (4, 08, 0)
@@ -748,7 +767,14 @@ let rec find_object meths type_expr =
               None
 
 let methods_of_object longident meths =
-  match lookup_env Env.lookup_value longident !Toploop.toplevel_env with
+  let lookup_value=
+#if OCAML_VERSION >= (4, 10, 0)
+    Env.find_value_by_name
+#else
+    Env.lookup_value
+#endif
+  in
+  match lookup_env lookup_value longident !Toploop.toplevel_env with
     | None ->
         []
     | Some (path, { val_type = type_expr }) ->
@@ -797,7 +823,14 @@ let rec labels_of_type acc type_expr =
         String_map.bindings acc
 
 let labels_of_function longident meths =
-  match lookup_env Env.lookup_value longident !Toploop.toplevel_env with
+  let lookup_value=
+#if OCAML_VERSION >= (4, 10, 0)
+    Env.find_value_by_name
+#else
+    Env.lookup_value
+#endif
+  in
+  match lookup_env lookup_value longident !Toploop.toplevel_env with
     | None ->
         []
     | Some (path, { val_type = type_expr }) ->
@@ -808,7 +841,14 @@ let labels_of_function longident meths =
               labels_of_type String_map.empty type_expr
 
 let labels_of_newclass longident =
-  match lookup_env Env.lookup_class longident !Toploop.toplevel_env with
+  let lookup_class=
+#if OCAML_VERSION >= (4, 10, 0)
+    Env.find_class_by_name
+#else
+    Env.lookup_class
+#endif
+  in
+  match lookup_env lookup_class longident !Toploop.toplevel_env with
     | None ->
         []
     | Some (path, { cty_new = None }) ->
diff --git a/src/lib/uTop_main.ml b/src/lib/uTop_main.ml
index 21484c5..8e36ad9 100644
--- a/src/lib/uTop_main.ml
+++ b/src/lib/uTop_main.ml
@@ -482,6 +482,10 @@ let rewrite_rules = [
   }
 ]
 
+#if OCAML_VERSION >= (4, 10, 0)
+let lookup_type longident env =
+  Env.find_type_by_name longident env
+#else
 #if OCAML_VERSION >= (4, 04, 0)
 let lookup_type longident env =
   let path = Env.lookup_type longident env in
@@ -489,6 +493,7 @@ let lookup_type longident env =
 #else
 let lookup_type = Env.lookup_type
 #endif
+#endif
 
 let rule_path rule =
   match rule.path_to_rewrite with
@@ -527,8 +532,15 @@ let rec is_persistent_path = function
 (* Check that the given long identifier is present in the environment
    and is persistent. *)
 let is_persistent_in_env longident =
+  let lookup_value=
+#if OCAML_VERSION >= (4, 10, 0)
+    Env.find_value_by_name
+#else
+    Env.lookup_value
+#endif
+  in
   try
-    is_persistent_path (fst (Env.lookup_value longident !Toploop.toplevel_env))
+    is_persistent_path (fst (lookup_value longident !Toploop.toplevel_env))
   with Not_found ->
     false
 
@@ -622,26 +634,22 @@ let bind_expressions name phrase =
    +-----------------------------------------------------------------+ *)
 
 #if OCAML_VERSION >= (4, 04, 0)
+
+#if OCAML_VERSION >= (4, 09, 0)
+  module Persistent_signature = Persistent_env.Persistent_signature
+#else
+  module Persistent_signature = Env.Persistent_signature
+#endif
+
 let execute_phrase =
   let new_cmis = ref []in
-
-  let default_load =
-#if OCAML_VERSION >= (4, 09, 0)
-    !Persistent_env.Persistent_signature.load
-#else
-    !Env.Persistent_signature.load
-#endif
-  in
+  let default_load = !Persistent_signature.load in
   let load ~unit_name =
     let res = default_load ~unit_name in
     (match res with None -> () | Some x -> new_cmis := x.cmi :: !new_cmis);
     res
   in
-#if OCAML_VERSION >= (4, 09, 0)
-  Persistent_env.Persistent_signature.load := load;
-#else
-  Env.Persistent_signature.load := load;
-#endif
+  Persistent_signature.load := load;
 
   let rec collect_printers path signature acc =
     List.fold_left (fun acc item ->
@@ -1173,6 +1181,22 @@ end
 let typeof sid =
   let id  = Longident.parse sid in
   let env = !Toploop.toplevel_env in
+#if OCAML_VERSION >= (4, 10, 0)
+  let lookup_value= Env.find_value_by_name
+  and lookup_label= Env.find_label_by_name
+  and lookup_modtype= Env.find_modtype_by_name
+  and lookup_module id env =
+    let path, decl = Env.find_module_by_name id env in
+    (path, decl.md_type)
+#else
+  let lookup_value= Env.lookup_value
+  and lookup_label= Env.lookup_label
+  and lookup_modtype= Env.lookup_modtype
+  and lookup_module id env =
+    let path = Env.lookup_module id env ~load:true in
+    (path, (Env.find_module path env).md_type)
+#endif
+  in
   let from_type_desc = function
     | Types.Tconstr (path, _, _) ->
       let typ_decl = Env.find_type path env in
@@ -1190,7 +1214,7 @@ let typeof sid =
       Some (Printtyp.tree_of_type_declaration id ty_decl Types.Trec_not)
     with Not_found ->
     try
-      let (path, val_descr) = Env.lookup_value id env in
+      let (path, val_descr) = lookup_value id env in
 #if OCAML_VERSION >= (4, 08, 0)
       let id = Ident.create_local (Path.name path) in
 #else
@@ -1199,7 +1223,7 @@ let typeof sid =
       Some (Printtyp.tree_of_value_description id val_descr)
     with Not_found ->
     try
-      let lbl_desc = Env.lookup_label id env in
+      let lbl_desc = lookup_label id env in
       let (path, ty_decl) = from_type_desc lbl_desc.Types.lbl_res.Types.desc in
 #if OCAML_VERSION >= (4, 08, 0)
       let id = Ident.create_local (Path.name path) in
@@ -1209,8 +1233,7 @@ let typeof sid =
       Some (Printtyp.tree_of_type_declaration id ty_decl Types.Trec_not)
     with Not_found ->
     try
-      let path = Env.lookup_module id env ~load:true in
-      let mod_typ = (Env.find_module path env).Types.md_type in
+      let path, mod_typ = lookup_module id env in
 #if OCAML_VERSION >= (4, 08, 0)
       let id = Ident.create_local (Path.name path) in
 #else
@@ -1219,7 +1242,7 @@ let typeof sid =
       Some (Printtyp.tree_of_module id mod_typ Types.Trec_not)
     with Not_found ->
     try
-      let (path, mty_decl) = Env.lookup_modtype id env in
+      let (path, mty_decl) = lookup_modtype id env in
 #if OCAML_VERSION >= (4, 08, 0)
       let id = Ident.create_local (Path.name path) in
 #else
@@ -1228,7 +1251,11 @@ let typeof sid =
       Some (Printtyp.tree_of_modtype_declaration id mty_decl)
     with Not_found ->
     try
+      #if OCAML_VERSION >= (4, 10, 0)
+      let cstr_desc = Env.find_constructor_by_name id env in
+      #else
       let cstr_desc = Env.lookup_constructor id env in
+      #endif
       match cstr_desc.Types.cstr_tag with
       | _ ->
         let (path, ty_decl) = from_type_desc cstr_desc.Types.cstr_res.Types.desc in