diff --git a/config/xConfigurator.ml b/config/xConfigurator.ml
index 268df4a..73e1850 100644
--- a/config/xConfigurator.ml
+++ b/config/xConfigurator.ml
@@ -8,7 +8,7 @@ let (!%) fmt = Printf.sprintf fmt
 module Configurator = struct
   include Configurator.V1
 
-  let ( ^/ ) = Caml.Filename.concat
+  let ( ^/ ) = Stdlib.Filename.concat
 
   let path_sep =
     if Sys.win32 then
@@ -19,7 +19,7 @@ module Configurator = struct
   let exe = if Sys.win32 then ".exe" else ""
 
   let get_path () =
-    match Caml.Sys.getenv "PATH" with
+    match Stdlib.Sys.getenv "PATH" with
     | exception Not_found -> []
     | s -> String.split ~on:path_sep s
 
@@ -27,7 +27,7 @@ module Configurator = struct
     List.find_map dirs ~f:(fun dir ->
       List.find_map bases ~f:(fun base ->
         let path = dir ^/ base in
-        if Caml.Sys.file_exists path then Some path else None))
+        if Stdlib.Sys.file_exists path then Some path else None))
 
   let find_program prog =
     let prog = prog ^ exe in
@@ -45,13 +45,13 @@ module Configurator = struct
     | s -> 
         (* findlib 1.7.3 installs META file for graphics 
            even when there is no graphics library installed. *)
-        let dest = Caml.Filename.temp_file "test" ".cma" in
-        let res = match Caml.Sys.command & !% "ocamlfind ocamlc -package %s -o %s -linkpkg" n dest with
+        let dest = Stdlib.Filename.temp_file "test" ".cma" in
+        let res = match Stdlib.Sys.command & !% "ocamlfind ocamlc -package %s -o %s -linkpkg" n dest with
           | 0 -> Some s
           | _ -> None
           | exception _ -> None
         in
-        (try Caml.Sys.remove dest with _ -> ());
+        (try Stdlib.Sys.remove dest with _ -> ());
         res
     | exception Findlib.No_such_package _ -> None
 
@@ -83,14 +83,14 @@ type item =
 module Make(A : sig val name : string end) = struct
   let t = create A.name
 
-  let log fmt = Caml.Format.eprintf fmt
+  let log fmt = Stdlib.Format.eprintf fmt
 
   module Package_conf = Package_conf
   open Package_conf
 
   let extract_package_conf xs =
-    Caml.List.fold_left merge empty
-      (Caml.List.map (fun item -> match item with
+    Stdlib.List.fold_left merge empty
+      (Stdlib.List.map (fun item -> match item with
            | Library (Some pkc) -> pkc
            | _ -> empty) xs)
 
@@ -167,8 +167,8 @@ module Make(A : sig val name : string end) = struct
   let by_cc ~c_flags ~link_flags ~headers ~functions:fnames () =
     log "Checking library %s by using C compiler... " (String.concat ~sep:" " link_flags);
     let headers = "stdio.h" :: headers in
-    let includes = Caml.List.map (!% "#include <%s>") headers in
-    let fcalls = Caml.List.map (!% "  ( (void(*)()) (%s) )();") fnames in
+    let includes = Stdlib.List.map (!% "#include <%s>") headers in
+    let fcalls = Stdlib.List.map (!% "  ( (void(*)()) (%s) )();") fnames in
     let code = 
       String.concat ~sep:"\n" 
       & includes 
diff --git a/core/images.ml b/core/images.ml
index 563ab7e..a53a6a4 100644
--- a/core/images.ml
+++ b/core/images.ml
@@ -102,7 +102,7 @@ let get_extension s =
   | _ -> s, ""
 
 let guess_extension s =
-  let s = String.lowercase s in
+  let s = String.lowercase_ascii s in
   match s with
   | "gif" -> Gif
   | "bmp" -> Bmp
diff --git a/core/units.ml b/core/units.ml
index 634bc9c..ddd6eae 100644
--- a/core/units.ml
+++ b/core/units.ml
@@ -30,7 +30,7 @@ let parse_length s = (* return in pt *)
     let digit,unit =
       if l > 2 then String.sub s 0 2, String.sub s (l-2) 2 else "", "" in
     try
-      (List.assoc (String.lowercase unit) units) *. float_of_string digit
+      (List.assoc (String.lowercase_ascii unit) units) *. float_of_string digit
     with
     | Not_found -> (* think it is in "pt" *)
       float_of_string s in