diff --git a/scripts/version.sh b/scripts/version.sh
index 8830b85dc..5ba85435b 100644
--- a/scripts/version.sh
+++ b/scripts/version.sh
@@ -1,4 +1,4 @@
 #! /bin/sh
 
 alpine_version=3.5
-ocaml_version=4.03.0
+ocaml_version=4.04.0
diff --git a/src/proto/alpha/qty_repr.ml b/src/proto/alpha/qty_repr.ml
index 81cd1d654..b3e632fbb 100644
--- a/src/proto/alpha/qty_repr.ml
+++ b/src/proto/alpha/qty_repr.ml
@@ -167,6 +167,7 @@ module Make (T: QTY) : S = struct
       | Ok res -> Ok res
       | Error ([ Addition_overflow _ ] as errs) ->
           Error (Multiplication_overflow (t, m) :: errs)
+      | Error errs -> Error errs
 
   let ( /? ) t d =
     if d <= 0L then
diff --git a/src/proto/environment/array.mli b/src/proto/environment/array.mli
index 872423df9..03a5e0567 100644
--- a/src/proto/environment/array.mli
+++ b/src/proto/environment/array.mli
@@ -13,6 +13,14 @@
 (*                                                                        *)
 (**************************************************************************)
 
+(* TEZOS CHANGES
+
+   * Import version 4.04.0
+   * Remove unsafe functions
+   * Remove deprecated functions
+
+*)
+
 (** Array operations. *)
 
 external length : 'a array -> int = "%array_length"
@@ -48,19 +56,11 @@ external make : int -> 'a -> 'a array = "caml_make_vect"
    If the value of [x] is a floating-point number, then the maximum
    size is only [Sys.max_array_length / 2].*)
 
-external create : int -> 'a -> 'a array = "caml_make_vect"
-  [@@ocaml.deprecated "Use Array.make instead."]
-(** @deprecated [Array.create] is an alias for {!Array.make}. *)
-
 external create_float: int -> float array = "caml_make_float_vect"
 (** [Array.create_float n] returns a fresh float array of length [n],
     with uninitialized data.
     @since 4.03 *)
 
-val make_float: int -> float array
-  [@@ocaml.deprecated "Use Array.create_float instead."]
-(** @deprecated [Array.make_float] is an alias for {!Array.create_float}. *)
-
 val init : int -> (int -> 'a) -> 'a array
 (** [Array.init n f] returns a fresh array of length [n],
    with element number [i] initialized to the result of [f i].
@@ -84,10 +84,6 @@ val make_matrix : int -> int -> 'a -> 'a array array
    If the value of [e] is a floating-point number, then the maximum
    size is only [Sys.max_array_length / 2]. *)
 
-val create_matrix : int -> int -> 'a -> 'a array array
-  [@@ocaml.deprecated "Use Array.make_matrix instead."]
-(** @deprecated [Array.create_matrix] is an alias for {!Array.make_matrix}. *)
-
 val append : 'a array -> 'a array -> 'a array
 (** [Array.append v1 v2] returns a fresh array containing the
    concatenation of the arrays [v1] and [v2]. *)
@@ -174,13 +170,15 @@ val fold_right : ('b -> 'a -> 'a) -> 'b array -> 'a -> 'a
 val iter2 : ('a -> 'b -> unit) -> 'a array -> 'b array -> unit
 (** [Array.iter2 f a b] applies function [f] to all the elements of [a]
    and [b].
-   Raise [Invalid_argument] if the arrays are not the same size. *)
+   Raise [Invalid_argument] if the arrays are not the same size.
+   @since 4.03.0 *)
 
 val map2 : ('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array
 (** [Array.map2 f a b] applies function [f] to all the elements of [a]
    and [b], and builds an array with the results returned by [f]:
    [[| f a.(0) b.(0); ...; f a.(Array.length a - 1) b.(Array.length b - 1)|]].
-   Raise [Invalid_argument] if the arrays are not the same size. *)
+   Raise [Invalid_argument] if the arrays are not the same size.
+   @since 4.03.0 *)
 
 
 (** {6 Array scanning} *)
@@ -189,20 +187,24 @@ val map2 : ('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array
 val for_all : ('a -> bool) -> 'a array -> bool
 (** [Array.for_all p [|a1; ...; an|]] checks if all elements of the array
    satisfy the predicate [p]. That is, it returns
-   [(p a1) && (p a2) && ... && (p an)]. *)
+   [(p a1) && (p a2) && ... && (p an)].
+   @since 4.03.0 *)
 
 val exists : ('a -> bool) -> 'a array -> bool
 (** [Array.exists p [|a1; ...; an|]] checks if at least one element of
     the array satisfies the predicate [p]. That is, it returns
-    [(p a1) || (p a2) || ... || (p an)]. *)
+    [(p a1) || (p a2) || ... || (p an)].
+    @since 4.03.0 *)
 
 val mem : 'a -> 'a array -> bool
 (** [mem a l] is true if and only if [a] is equal
-   to an element of [l]. *)
+   to an element of [l].
+   @since 4.03.0 *)
 
 val memq : 'a -> 'a array -> bool
 (** Same as {!Array.mem}, but uses physical equality instead of structural
-   equality to compare array elements. *)
+   equality to compare array elements.
+   @since 4.03.0 *)
 
 
 (** {6 Sorting} *)
@@ -249,11 +251,3 @@ val fast_sort : ('a -> 'a -> int) -> 'a array -> unit
     on typical input.
 *)
 
-
-(**/**)
-(** {6 Undocumented functions} *)
-
-(* The following is for system use only. Do not call directly. *)
-
-external unsafe_get : 'a array -> int -> 'a = "%array_unsafe_get"
-external unsafe_set : 'a array -> int -> 'a -> unit = "%array_unsafe_set"
diff --git a/src/proto/environment/buffer.mli b/src/proto/environment/buffer.mli
index ed379f0ed..dde414691 100644
--- a/src/proto/environment/buffer.mli
+++ b/src/proto/environment/buffer.mli
@@ -1,20 +1,22 @@
-(***********************************************************************)
-(*                                                                     *)
-(*                                OCaml                                *)
-(*                                                                     *)
-(*  Pierre Weis and Xavier Leroy, projet Cristal, INRIA Rocquencourt   *)
-(*                                                                     *)
-(*  Copyright 1999 Institut National de Recherche en Informatique et   *)
-(*  en Automatique.  All rights reserved.  This file is distributed    *)
-(*  under the terms of the GNU Library General Public License, with    *)
-(*  the special exception on linking described in file ../LICENSE.     *)
-(*                                                                     *)
-(***********************************************************************)
+(**************************************************************************)
+(*                                                                        *)
+(*                                 OCaml                                  *)
+(*                                                                        *)
+(*   Pierre Weis and Xavier Leroy, projet Cristal, INRIA Rocquencourt     *)
+(*                                                                        *)
+(*   Copyright 1999 Institut National de Recherche en Informatique et     *)
+(*     en Automatique.                                                    *)
+(*                                                                        *)
+(*   All rights reserved.  This file is distributed under the terms of    *)
+(*   the GNU Lesser General Public License version 2.1, with the          *)
+(*   special exception on linking described in the file LICENSE.          *)
+(*                                                                        *)
+(**************************************************************************)
 
 (* TEZOS CHANGES
 
-   * import version 4.02.1
-   * Removed channel functions
+   * Import version 4.04.0
+   * Remove channel functions
 
 *)
 
@@ -45,17 +47,19 @@ val create : int -> t
 
 val contents : t -> string
 (** Return a copy of the current contents of the buffer.
-   The buffer itself is unchanged. *)
+    The buffer itself is unchanged. *)
 
 val to_bytes : t -> bytes
 (** Return a copy of the current contents of the buffer.
-   The buffer itself is unchanged. *)
+    The buffer itself is unchanged.
+    @since 4.02 *)
 
 val sub : t -> int -> int -> string
-(** [Buffer.sub b off len] returns (a copy of) the bytes from the
-    current contents of the buffer [b] starting at offset [off] of
-    length [len] bytes. May raise [Invalid_argument] if out of bounds
-    request. The buffer itself is unaffected. *)
+(** [Buffer.sub b off len] returns a copy of [len] bytes from the
+    current contents of the buffer [b], starting at offset [off].
+
+    Raise [Invalid_argument] if [srcoff] and [len] do not designate a valid
+    range of [b]. *)
 
 val blit : t -> int -> bytes -> int -> int -> unit
 (** [Buffer.blit src srcoff dst dstoff len] copies [len] characters from
@@ -69,7 +73,7 @@ val blit : t -> int -> bytes -> int -> int -> unit
 *)
 
 val nth : t -> int -> char
-(** get the n-th character of the buffer. Raise [Invalid_argument] if
+(** Get the n-th character of the buffer. Raise [Invalid_argument] if
     index out of bounds *)
 
 val length : t -> int
@@ -86,25 +90,27 @@ val reset : t -> unit
    faster reclamation of the space used by the buffer. *)
 
 val add_char : t -> char -> unit
-(** [add_char b c] appends the character [c] at the end of the buffer [b]. *)
+(** [add_char b c] appends the character [c] at the end of buffer [b]. *)
 
 val add_string : t -> string -> unit
-(** [add_string b s] appends the string [s] at the end of the buffer [b]. *)
+(** [add_string b s] appends the string [s] at the end of buffer [b]. *)
 
 val add_bytes : t -> bytes -> unit
-(** [add_string b s] appends the string [s] at the end of the buffer [b]. *)
+(** [add_bytes b s] appends the byte sequence [s] at the end of buffer [b].
+    @since 4.02 *)
 
 val add_substring : t -> string -> int -> int -> unit
 (** [add_substring b s ofs len] takes [len] characters from offset
-   [ofs] in string [s] and appends them at the end of the buffer [b]. *)
+   [ofs] in string [s] and appends them at the end of buffer [b]. *)
 
 val add_subbytes : t -> bytes -> int -> int -> unit
-(** [add_substring b s ofs len] takes [len] characters from offset
-   [ofs] in byte sequence [s] and appends them at the end of the buffer [b]. *)
+(** [add_subbytes b s ofs len] takes [len] characters from offset
+    [ofs] in byte sequence [s] and appends them at the end of buffer [b].
+    @since 4.02 *)
 
 val add_substitute : t -> (string -> string) -> string -> unit
 (** [add_substitute b f s] appends the string pattern [s] at the end
-   of the buffer [b] with substitution.
+   of buffer [b] with substitution.
    The substitution process looks for variables into
    the pattern and substitutes each variable name by its value, as
    obtained by applying the mapping [f] to the variable name. Inside the
diff --git a/src/proto/environment/bytes.mli b/src/proto/environment/bytes.mli
index 4d9276ce7..539e9d01d 100644
--- a/src/proto/environment/bytes.mli
+++ b/src/proto/environment/bytes.mli
@@ -13,6 +13,15 @@
 (*                                                                        *)
 (**************************************************************************)
 
+(* TEZOS CHANGES
+
+   * Import version 4.04.0
+   * Remove unsafe functions
+   * Remove deprecated functions
+   * Add binary data insertion / extraction functions
+
+*)
+
 (** Byte sequence operations.
 
    A byte sequence is a mutable data structure that contains a
@@ -42,21 +51,21 @@
    @since 4.02.0
  *)
 
-external length : bytes -> int = "%string_length"
+external length : bytes -> int = "%bytes_length"
 (** Return the length (number of bytes) of the argument. *)
 
-external get : bytes -> int -> char = "%string_safe_get"
+external get : bytes -> int -> char = "%bytes_safe_get"
 (** [get s n] returns the byte at index [n] in argument [s].
 
     Raise [Invalid_argument] if [n] not a valid index in [s]. *)
 
-external set : bytes -> int -> char -> unit = "%string_safe_set"
+external set : bytes -> int -> char -> unit = "%bytes_safe_set"
 (** [set s n c] modifies [s] in place, replacing the byte at index [n]
     with [c].
 
     Raise [Invalid_argument] if [n] is not a valid index in [s]. *)
 
-external create : int -> bytes = "caml_create_string"
+external create : int -> bytes = "caml_create_bytes"
 (** [create n] returns a new byte sequence of length [n]. The
     sequence is uninitialized and contains arbitrary bytes.
 
@@ -232,32 +241,6 @@ val rcontains_from : bytes -> int -> char -> bool
     Raise [Invalid_argument] if [stop < 0] or [stop+1] is not a valid
     position in [s]. *)
 
-val uppercase : bytes -> bytes
-  [@@ocaml.deprecated "Use Bytes.uppercase_ascii instead."]
-(** Return a copy of the argument, with all lowercase letters
-   translated to uppercase, including accented letters of the ISO
-   Latin-1 (8859-1) character set.
-   @deprecated Functions operating on Latin-1 character set are deprecated. *)
-
-val lowercase : bytes -> bytes
-  [@@ocaml.deprecated "Use Bytes.lowercase_ascii instead."]
-(** Return a copy of the argument, with all uppercase letters
-   translated to lowercase, including accented letters of the ISO
-   Latin-1 (8859-1) character set.
-   @deprecated Functions operating on Latin-1 character set are deprecated. *)
-
-val capitalize : bytes -> bytes
-  [@@ocaml.deprecated "Use Bytes.capitalize_ascii instead."]
-(** Return a copy of the argument, with the first character set to uppercase,
-   using the ISO Latin-1 (8859-1) character set..
-   @deprecated Functions operating on Latin-1 character set are deprecated. *)
-
-val uncapitalize : bytes -> bytes
-  [@@ocaml.deprecated "Use Bytes.uncapitalize_ascii instead."]
-(** Return a copy of the argument, with the first character set to lowercase,
-   using the ISO Latin-1 (8859-1) character set..
-   @deprecated Functions operating on Latin-1 character set are deprecated. *)
-
 val uppercase_ascii : bytes -> bytes
 (** Return a copy of the argument, with all lowercase letters
    translated to uppercase, using the US-ASCII character set.
diff --git a/src/proto/environment/format.mli b/src/proto/environment/format.mli
index e9a500129..6c12319da 100644
--- a/src/proto/environment/format.mli
+++ b/src/proto/environment/format.mli
@@ -15,10 +15,10 @@
 
 (* TEZOS CHANGES
 
-   * import version 4.03.0
-   * Removed channel functions
-   * Removed toplevel effect based functions
-   * Removed deprecated functions
+   * Import version 4.04.0
+   * Remove channel functions
+   * Remove toplevel effect based functions
+   * Remove deprecated functions
 
 *)
 
@@ -83,15 +83,48 @@
    the evaluation order of printing commands.
 *)
 
+(** {6:tags Semantic Tags} *)
+
+type tag = string
+
+(** {6:meaning Changing the meaning of standard formatter pretty printing} *)
+
+(** The [Format] module is versatile enough to let you completely redefine
+  the meaning of pretty printing: you may provide your own functions to define
+  how to handle indentation, line splitting, and even printing of all the
+  characters that have to be printed! *)
+
+type formatter_out_functions = {
+  out_string : string -> int -> int -> unit;
+  out_flush : unit -> unit;
+  out_newline : unit -> unit;
+  out_spaces : int -> unit;
+}
+
+(** {6:tagsmeaning Changing the meaning of printing semantic tags} *)
+
+type formatter_tag_functions = {
+  mark_open_tag : tag -> string;
+  mark_close_tag : tag -> string;
+  print_open_tag : tag -> unit;
+  print_close_tag : tag -> unit;
+}
+(** The tag handling functions specific to a formatter:
+  [mark] versions are the 'tag marking' functions that associate a string
+  marker to a tag in order for the pretty-printing engine to flush
+  those markers as 0 length tokens in the output device of the formatter.
+  [print] versions are the 'tag printing' functions that can perform
+  regular printing when a tag is closed or opened. *)
+
 (** {6 Multiple formatted output} *)
 
-type formatter;;
+type formatter
 (** Abstract data corresponding to a pretty-printer (also called a
   formatter) and all its machinery.
 
   Defining new pretty-printers permits unrelated output of material in
   parallel on several output channels.
-  All the parameters of a pretty-printer are local to this pretty-printer:
+  All the parameters of a pretty-printer are local to a formatter:
   margin, maximum indentation limit, maximum number of boxes
   simultaneously opened, ellipsis, and so on, are specific to
   each pretty-printer and may be fixed independently.
@@ -154,6 +187,36 @@ val pp_over_max_boxes : formatter -> unit -> bool
 val pp_set_ellipsis_text : formatter -> string -> unit
 val pp_get_ellipsis_text : formatter -> unit -> string
 
+val pp_set_formatter_output_functions :
+  formatter -> (string -> int -> int -> unit) -> (unit -> unit) -> unit
+
+val pp_get_formatter_output_functions :
+  formatter -> unit -> (string -> int -> int -> unit) * (unit -> unit)
+
+val pp_set_formatter_tag_functions :
+  formatter -> formatter_tag_functions -> unit
+
+val pp_get_formatter_tag_functions :
+  formatter -> unit -> formatter_tag_functions
+
+val pp_set_formatter_out_functions :
+  formatter -> formatter_out_functions -> unit
+
+val pp_get_formatter_out_functions :
+  formatter -> unit -> formatter_out_functions
+(** These functions are the basic ones: usual functions
+   operating on the standard formatter are defined via partial
+   evaluation of these primitives. For instance,
+   [print_string] is equal to [pp_print_string std_formatter]. *)
+
+val pp_flush_formatter : formatter -> unit
+(** [pp_flush_formatter fmt] flushes [fmt]'s internal queue, ensuring that all
+    the printing and flushing actions have been performed. In addition, this
+    operation will close all boxes and reset the state of the formatter.
+
+    This will not flush [fmt]'s output. In most cases, the user may want to use
+    {!pp_print_flush} instead. *)
+
 (** {6 Convenience formatting functions.} *)
 
 val pp_print_list:
diff --git a/src/proto/environment/int32.mli b/src/proto/environment/int32.mli
index 249fa23db..170a8226e 100644
--- a/src/proto/environment/int32.mli
+++ b/src/proto/environment/int32.mli
@@ -13,6 +13,13 @@
 (*                                                                        *)
 (**************************************************************************)
 
+(* TEZOS CHANGES
+
+   * Import version 4.04.0
+   * Remove deprecated functions
+
+*)
+
 (** 32-bit integers.
 
    This module provides operations on the type [int32]
@@ -167,10 +174,3 @@ val equal: t -> t -> bool
 (** The equal function for int32s.
     @since 4.03.0 *)
 
-(**/**)
-
-(** {6 Deprecated functions} *)
-
-external format : string -> int32 -> string = "caml_int32_format"
-(** Do not use this deprecated function.  Instead,
-   used {!Printf.sprintf} with a [%l...] format. *)
diff --git a/src/proto/environment/int64.mli b/src/proto/environment/int64.mli
index 85df21fe2..14a7fcc8a 100644
--- a/src/proto/environment/int64.mli
+++ b/src/proto/environment/int64.mli
@@ -13,6 +13,12 @@
 (*                                                                        *)
 (**************************************************************************)
 
+(* TEZOS CHANGES
+
+   * Import version 4.04.0
+   * Remove deprecated functions
+
+*)
 (** 64-bit integers.
 
    This module provides operations on the type [int64] of
@@ -188,11 +194,3 @@ val compare: t -> t -> int
 val equal: t -> t -> bool
 (** The equal function for int64s.
     @since 4.03.0 *)
-
-(**/**)
-
-(** {6 Deprecated functions} *)
-
-external format : string -> int64 -> string = "caml_int64_format"
-(** Do not use this deprecated function.  Instead,
-   used {!Printf.sprintf} with a [%L...] format. *)
diff --git a/src/proto/environment/list.mli b/src/proto/environment/list.mli
index 10ea35883..7d12712a1 100644
--- a/src/proto/environment/list.mli
+++ b/src/proto/environment/list.mli
@@ -67,8 +67,7 @@ val concat : 'a list list -> 'a list
    (length of the argument + length of the longest sub-list). *)
 
 val flatten : 'a list list -> 'a list
-(** Same as [concat].  Not tail-recursive
-   (length of the argument + length of the longest sub-list). *)
+(** An alias for [concat]. *)
 
 
 (** {6 Iterators} *)
diff --git a/src/proto/environment/pervasives.mli b/src/proto/environment/pervasives.mli
index d227e8f2b..35e65e2f3 100644
--- a/src/proto/environment/pervasives.mli
+++ b/src/proto/environment/pervasives.mli
@@ -15,9 +15,12 @@
 
 (* TEZOS CHANGES
 
-   * import version 4.02.1
-   * Removed [channel], [exit], ...
-   * Removed polymorphic comparisons
+   * Import version 4.04.0
+   * Remove [channel], [exit], ...
+   * Remove polymorphic comparisons
+   * Remove non IEEE754-standardized functions on floats
+   * Remove deprecated functions
+
 *)
 
 
@@ -38,7 +41,7 @@
 external raise : exn -> 'a = "%raise"
 (** Raise the given exception value *)
 
-(* external raise_notrace : exn -> 'a = "%raise_notrace" *)
+external raise_notrace : exn -> 'a = "%raise_notrace"
 (** A faster version [raise] which does not record the backtrace.
     @since 4.02.0
 *)
@@ -46,7 +49,7 @@ external raise : exn -> 'a = "%raise"
 val invalid_arg : string -> 'a
 (** Raise exception [Invalid_argument] with the given string. *)
 
-(* val failwith : string -> 'a *)
+val failwith : string -> 'a
 (** Raise exception [Failure] with the given string. *)
 
 exception Exit
@@ -64,56 +67,72 @@ external ( && ) : bool -> bool -> bool = "%sequand"
    in [e1 && e2], [e1] is evaluated first, and if it returns [false],
    [e2] is not evaluated at all. *)
 
-external ( & ) : bool -> bool -> bool = "%sequand"
-(** @deprecated {!Pervasives.( && )} should be used instead. *)
 
 external ( || ) : bool -> bool -> bool = "%sequor"
 (** The boolean 'or'. Evaluation is sequential, left-to-right:
    in [e1 || e2], [e1] is evaluated first, and if it returns [true],
    [e2] is not evaluated at all. *)
 
-external ( or ) : bool -> bool -> bool = "%sequor"
-  [@@ocaml.deprecated "Use (||) instead."]
-(** @deprecated {!Pervasives.( || )} should be used instead.*)
-
 (** {6 Debugging} *)
 
 external __LOC__ : string = "%loc_LOC"
 (** [__LOC__] returns the location at which this expression appears in
     the file currently being parsed by the compiler, with the standard
-    error format of OCaml: "File %S, line %d, characters %d-%d" *)
+    error format of OCaml: "File %S, line %d, characters %d-%d".
+    @since 4.02.0
+*)
+
 external __FILE__ : string = "%loc_FILE"
 (** [__FILE__] returns the name of the file currently being
-    parsed by the compiler. *)
+    parsed by the compiler.
+    @since 4.02.0
+*)
+
 external __LINE__ : int = "%loc_LINE"
 (** [__LINE__] returns the line number at which this expression
-    appears in the file currently being parsed by the compiler. *)
+    appears in the file currently being parsed by the compiler.
+    @since 4.02.0
+*)
+
 external __MODULE__ : string = "%loc_MODULE"
 (** [__MODULE__] returns the module name of the file being
-    parsed by the compiler. *)
+    parsed by the compiler.
+    @since 4.02.0
+*)
+
 external __POS__ : string * int * int * int = "%loc_POS"
 (** [__POS__] returns a tuple [(file,lnum,cnum,enum)], corresponding
     to the location at which this expression appears in the file
     currently being parsed by the compiler. [file] is the current
     filename, [lnum] the line number, [cnum] the character position in
-    the line and [enum] the last character position in the line. *)
+    the line and [enum] the last character position in the line.
+    @since 4.02.0
+ *)
 
 external __LOC_OF__ : 'a -> string * 'a = "%loc_LOC"
 (** [__LOC_OF__ expr] returns a pair [(loc, expr)] where [loc] is the
     location of [expr] in the file currently being parsed by the
     compiler, with the standard error format of OCaml: "File %S, line
-    %d, characters %d-%d" *)
+    %d, characters %d-%d".
+    @since 4.02.0
+*)
+
 external __LINE_OF__ : 'a -> int * 'a = "%loc_LINE"
 (** [__LINE__ expr] returns a pair [(line, expr)], where [line] is the
     line number at which the expression [expr] appears in the file
-    currently being parsed by the compiler. *)
+    currently being parsed by the compiler.
+    @since 4.02.0
+ *)
+
 external __POS_OF__ : 'a -> (string * int * int * int) * 'a = "%loc_POS"
-(** [__POS_OF__ expr] returns a pair [(expr,loc)], where [loc] is a
+(** [__POS_OF__ expr] returns a pair [(loc,expr)], where [loc] is a
     tuple [(file,lnum,cnum,enum)] corresponding to the location at
     which the expression [expr] appears in the file currently being
     parsed by the compiler. [file] is the current filename, [lnum] the
     line number, [cnum] the character position in the line and [enum]
-    the last character position in the line. *)
+    the last character position in the line.
+    @since 4.02.0
+ *)
 
 (** {6 Composition operators} *)
 
@@ -556,5 +575,27 @@ type ('a, 'b, 'c, 'd) format4 = ('a, 'b, 'c, 'c, 'c, 'd) format6
 
 type ('a, 'b, 'c) format = ('a, 'b, 'c, 'c) format4
 
+val string_of_format : ('a, 'b, 'c, 'd, 'e, 'f) format6 -> string
+(** Converts a format string into a string. *)
 
+external format_of_string :
+  ('a, 'b, 'c, 'd, 'e, 'f) format6 ->
+  ('a, 'b, 'c, 'd, 'e, 'f) format6 = "%identity"
+(** [format_of_string s] returns a format string read from the string
+    literal [s].
+    Note: [format_of_string] can not convert a string argument that is not a
+    literal. If you need this functionality, use the more general
+    {!Scanf.format_from_string} function.
+*)
+
+val ( ^^ ) :
+  ('a, 'b, 'c, 'd, 'e, 'f) format6 ->
+  ('f, 'b, 'c, 'e, 'g, 'h) format6 ->
+  ('a, 'b, 'c, 'd, 'g, 'h) format6
+(** [f1 ^^ f2] catenates format strings [f1] and [f2]. The result is a
+  format string that behaves as the concatenation of format strings [f1] and
+  [f2]: in case of formatted output, it accepts arguments from [f1], then
+  arguments from [f2]; in case of formatted input, it returns results from
+  [f1], then results from [f2].
+*)
 
diff --git a/src/proto/environment/set.mli b/src/proto/environment/set.mli
index 5d968e0cf..f57999eb1 100644
--- a/src/proto/environment/set.mli
+++ b/src/proto/environment/set.mli
@@ -118,6 +118,17 @@ module type S =
        The elements of [s] are presented to [f] in increasing order
        with respect to the ordering over the type of the elements. *)
 
+    val map: (elt -> elt) -> t -> t
+    (** [map f s] is the set whose elements are [f a0],[f a1]... [f
+        aN], where [a0],[a1]...[aN] are the elements of [s].
+
+       The elements are passed to [f] in increasing order
+       with respect to the ordering over the type of the elements.
+
+       If no element of [s] is changed by [f], [s] is returned
+       unchanged. (If each output of [f] is physically equal to its
+       input, the returned set is physically equal to [s].) *)
+
     val fold: (elt -> 'a -> 'a) -> t -> 'a -> 'a
     (** [fold f s a] computes [(f xN ... (f x2 (f x1 a))...)],
        where [x1 ... xN] are the elements of [s], in increasing order. *)
diff --git a/src/proto/environment/string.mli b/src/proto/environment/string.mli
index 50693ff14..73ff181f4 100644
--- a/src/proto/environment/string.mli
+++ b/src/proto/environment/string.mli
@@ -1,15 +1,26 @@
-(***********************************************************************)
-(*                                                                     *)
-(*                                OCaml                                *)
-(*                                                                     *)
-(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
-(*                                                                     *)
-(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
-(*  en Automatique.  All rights reserved.  This file is distributed    *)
-(*  under the terms of the GNU Library General Public License, with    *)
-(*  the special exception on linking described in file ../LICENSE.     *)
-(*                                                                     *)
-(***********************************************************************)
+(**************************************************************************)
+(*                                                                        *)
+(*                                 OCaml                                  *)
+(*                                                                        *)
+(*             Xavier Leroy, projet Cristal, INRIA Rocquencourt           *)
+(*                                                                        *)
+(*   Copyright 1996 Institut National de Recherche en Informatique et     *)
+(*     en Automatique.                                                    *)
+(*                                                                        *)
+(*   All rights reserved.  This file is distributed under the terms of    *)
+(*   the GNU Lesser General Public License version 2.1, with the          *)
+(*   special exception on linking described in the file LICENSE.          *)
+(*                                                                        *)
+(**************************************************************************)
+
+(* TEZOS CHANGES
+
+   * Import version 4.04.0
+   * Remove unsafe functions
+   * Remove deprecated functions (enforcing string immutability)
+   * Add binary data extraction functions
+
+*)
 
 (** String operations.
 
@@ -30,20 +41,6 @@
   substring of [s] if [len >= 0] and [start] and [start+len] are
   valid positions in [s].
 
-  OCaml strings used to be modifiable in place, for instance via the
-  {!String.set} and {!String.blit} functions described below. This
-  usage is deprecated and only possible when the compiler is put in
-  "unsafe-string" mode by giving the [-unsafe-string] command-line
-  option (which is currently the default for reasons of backward
-  compatibility). This is done by making the types [string] and
-  [bytes] (see module {!Bytes}) interchangeable so that functions
-  expecting byte sequences can also accept strings as arguments and
-  modify them.
-
-  All new code should avoid this feature and be compiled with the
-  [-safe-string] command-line option to enforce the separation between
-  the types [string] and [bytes].
-
  *)
 
 external length : string -> int = "%string_length"
@@ -56,25 +53,6 @@ external get : string -> int -> char = "%string_safe_get"
    Raise [Invalid_argument] if [n] not a valid index in [s]. *)
 
 
-external set : bytes -> int -> char -> unit = "%string_safe_set"
-  [@@ocaml.deprecated "Use Bytes.set instead."]
-(** [String.set s n c] modifies byte sequence [s] in place,
-   replacing the byte at index [n] with [c].
-   You can also write [s.[n] <- c] instead of [String.set s n c].
-
-   Raise [Invalid_argument] if [n] is not a valid index in [s].
-
-   @deprecated This is a deprecated alias of {!Bytes.set}.[ ] *)
-
-external create : int -> bytes = "caml_create_string"
-  [@@ocaml.deprecated "Use Bytes.create instead."]
-(** [String.create n] returns a fresh byte sequence of length [n].
-   The sequence is uninitialized and contains arbitrary bytes.
-
-   Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}.
-
-   @deprecated This is a deprecated alias of {!Bytes.create}.[ ] *)
-
 val make : int -> char -> string
 (** [String.make n c] returns a fresh string of length [n],
    filled with the character [c].
@@ -91,12 +69,6 @@ val init : int -> (int -> char) -> string
     @since 4.02.0
 *)
 
-val copy : string -> string [@@ocaml.deprecated]
-(** Return a copy of the given string.
-
-    @deprecated Because strings are immutable, it doesn't make much
-    sense to make identical copies of them. *)
-
 val sub : string -> int -> int -> string
 (** [String.sub s start len] returns a fresh string of length [len],
    containing the substring of [s] that starts at position [start] and
@@ -105,16 +77,6 @@ val sub : string -> int -> int -> string
    Raise [Invalid_argument] if [start] and [len] do not
    designate a valid substring of [s]. *)
 
-val fill : bytes -> int -> int -> char -> unit
-  [@@ocaml.deprecated "Use Bytes.fill instead."]
-(** [String.fill s start len c] modifies byte sequence [s] in place,
-   replacing [len] bytes with [c], starting at [start].
-
-   Raise [Invalid_argument] if [start] and [len] do not
-   designate a valid range of [s].
-
-   @deprecated This is a deprecated alias of {!Bytes.fill}.[ ] *)
-
 val blit : string -> int -> bytes -> int -> int -> unit
 (** Same as {!Bytes.blit_string}. *)
 
@@ -158,13 +120,20 @@ val trim : string -> string
 
 val escaped : string -> string
 (** Return a copy of the argument, with special characters
-   represented by escape sequences, following the lexical
-   conventions of OCaml.  If there is no special
-   character in the argument, return the original string itself,
-   not a copy. Its inverse function is Scanf.unescaped.
+    represented by escape sequences, following the lexical
+    conventions of OCaml.
+    All characters outside the ASCII printable range (32..126) are
+    escaped, as well as backslash and double-quote.
 
-   Raise [Invalid_argument] if the result is longer than
-   {!Sys.max_string_length} bytes. *)
+    If there is no special character in the argument that needs
+    escaping, return the original string itself, not a copy.
+
+    Raise [Invalid_argument] if the result is longer than
+    {!Sys.max_string_length} bytes.
+
+    The function {!Scanf.unescaped} is a left inverse of [escaped],
+    i.e. [Scanf.unescaped (escaped s) = s] for any string [s] (unless
+    [escape s] fails). *)
 
 val index : string -> char -> int
 (** [String.index s c] returns the index of the first
@@ -214,21 +183,25 @@ val rcontains_from : string -> int -> char -> bool
    Raise [Invalid_argument] if [stop < 0] or [stop+1] is not a valid
    position in [s]. *)
 
-val uppercase : string -> string
+val uppercase_ascii : string -> string
 (** Return a copy of the argument, with all lowercase letters
-   translated to uppercase, including accented letters of the ISO
-   Latin-1 (8859-1) character set. *)
+   translated to uppercase, using the US-ASCII character set.
+   @since 4.03.0 *)
 
-val lowercase : string -> string
+val lowercase_ascii : string -> string
 (** Return a copy of the argument, with all uppercase letters
-   translated to lowercase, including accented letters of the ISO
-   Latin-1 (8859-1) character set. *)
+   translated to lowercase, using the US-ASCII character set.
+   @since 4.03.0 *)
 
-val capitalize : string -> string
-(** Return a copy of the argument, with the first character set to uppercase. *)
+val capitalize_ascii : string -> string
+(** Return a copy of the argument, with the first character set to uppercase,
+   using the US-ASCII character set.
+   @since 4.03.0 *)
 
-val uncapitalize : string -> string
-(** Return a copy of the argument, with the first character set to lowercase. *)
+val uncapitalize_ascii : string -> string
+(** Return a copy of the argument, with the first character set to lowercase,
+   using the US-ASCII character set.
+   @since 4.03.0 *)
 
 type t = string
 (** An alias for the type of strings. *)
@@ -239,6 +212,24 @@ val compare: t -> t -> int
     allows the module [String] to be passed as argument to the functors
     {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equal function for strings.
+    @since 4.03.0 *)
+
+val split_on_char: char -> string -> string list
+(** [String.split_on_char sep s] returns the list of all (possibly empty)
+    substrings of [s] that are delimited by the [sep] character.
+
+    The function's output is specified by the following invariants:
+
+    - The list is not empty.
+    - Concatenating its elements using [sep] as a separator returns a
+      string equal to the input ([String.concat (String.make 1 sep)
+      (String.split_on_char sep s) = s]).
+    - No string in the result contains the [sep] character.
+
+    @since 4.04.0
+*)
 
 (** Functions reading bytes  *)