diff --git a/src/core/CCPair.ml b/src/core/CCPair.ml
index 875d4167..1e24a082 100644
--- a/src/core/CCPair.ml
+++ b/src/core/CCPair.ml
@@ -2,27 +2,53 @@
 
 (** {1 Tuple Functions} *)
 
+[@@@ifge 5.4]
+
+include Pair
+
+[@@@else_]
+
 type ('a, 'b) t = 'a * 'b
 
 let make x y = x, y
+let fst = fst
+let snd = snd
+let swap (x, y) = y, x
 let map_fst f (x, y) = f x, y
 let map_snd f (x, y) = x, f y
 let map f g (x, y) = f x, g y
+
+[@@@endif]
+
 let map_same f (x, y) = f x, f y
 let map2 f g (a, b) (x, y) = f a x, g b y
 let map_same2 f (a, b) (x, y) = f a x, f b y
 let fst_map f (x, _) = f x
 let snd_map f (_, x) = f x
+
+[@@@iflt 5.4]
+
 let iter f (x, y) = f x y
-let swap (x, y) = y, x
+
+[@@@endif]
+
 let ( <<< ) = map_fst
 let ( >>> ) = map_snd
 let ( *** ) = map
 let ( &&& ) f g x = f x, g x
 let merge f (x, y) = f x y
+
+[@@@iflt 5.4]
+
 let fold = merge
+
+[@@@endif]
+
 let dup x = x, x
 let dup_map f x = x, f x
+
+[@@@iflt 5.4]
+
 let equal f g (x1, y1) (x2, y2) = f x1 x2 && g y1 y2
 
 let compare f g (x1, y1) (x2, y2) =
@@ -32,6 +58,8 @@ let compare f g (x1, y1) (x2, y2) =
   else
     g y1 y2
 
+[@@@endif]
+
 let to_string ?(sep = ", ") a_to_string b_to_string (x, y) =
   Printf.sprintf "%s%s%s" (a_to_string x) sep (b_to_string y)
 
diff --git a/src/core/CCPair.mli b/src/core/CCPair.mli
index 2492bbde..76cd1af0 100644
--- a/src/core/CCPair.mli
+++ b/src/core/CCPair.mli
@@ -2,12 +2,27 @@
 
 (** Tuple Functions *)
 
+[@@@ifge 5.4]
+
+include module type of Pair
+
+[@@@else_]
+
 type ('a, 'b) t = 'a * 'b
 
 val make : 'a -> 'b -> ('a, 'b) t
 (** Make a tuple from its components.
     @since 0.16 *)
 
+val fst : 'a * 'b -> 'a
+(** [fst (a, b)] returns [a] *)
+
+val snd : 'a * 'b -> 'b
+(** [snd (a, b)] returns [b] *)
+
+val swap : 'a * 'b -> 'b * 'a
+(** Swap the components of the tuple. *)
+
 val map_fst : ('a -> 'b) -> 'a * 'c -> 'b * 'c
 (** [map_fst f (x, y)] returns [(f x, y)].
     Renamed from [map1] since 3.0. *)
@@ -19,6 +34,8 @@ val map_snd : ('a -> 'b) -> 'c * 'a -> 'c * 'b
 val map : ('a -> 'c) -> ('b -> 'd) -> 'a * 'b -> 'c * 'd
 (** Synonym to {!( *** )}. Map on both sides of a tuple. *)
 
+[@@@endif]
+
 val map_same : ('a -> 'b) -> 'a * 'a -> 'b * 'b
 (** Like {!map} but specialized for pairs with elements of the same type. *)
 
@@ -45,10 +62,11 @@ val snd_map : ('a -> 'b) -> _ * 'a -> 'b
     Rename from [map_snd] since 3.0.
     @since 0.3.3 *)
 
+[@@@iflt 5.4]
+
 val iter : ('a -> 'b -> unit) -> 'a * 'b -> unit
 
-val swap : 'a * 'b -> 'b * 'a
-(** Swap the components of the tuple. *)
+[@@@endif]
 
 val ( <<< ) : ('a -> 'b) -> 'a * 'c -> 'b * 'c
 (** Map on the left side of the tuple. *)
@@ -66,10 +84,14 @@ val ( &&& ) : ('a -> 'b) -> ('a -> 'c) -> 'a -> 'b * 'c
 val merge : ('a -> 'b -> 'c) -> 'a * 'b -> 'c
 (** Uncurrying (merges the two components of a tuple). *)
 
+[@@@iflt 5.4]
+
 val fold : ('a -> 'b -> 'c) -> 'a * 'b -> 'c
 (** Synonym to {!merge}.
     @since 0.3.3 *)
 
+[@@@endif]
+
 val dup : 'a -> 'a * 'a
 (** [dup x = (x,x)] (duplicate the value).
     @since 0.3.3 *)
@@ -79,12 +101,16 @@ val dup_map : ('a -> 'b) -> 'a -> 'a * 'b
     to the second copy.
     @since 0.3.3 *)
 
+[@@@iflt 5.4]
+
 val equal :
   ('a -> 'a -> bool) -> ('b -> 'b -> bool) -> 'a * 'b -> 'a * 'b -> bool
 
 val compare :
   ('a -> 'a -> int) -> ('b -> 'b -> int) -> 'a * 'b -> 'a * 'b -> int
 
+[@@@endif]
+
 val to_string :
   ?sep:string -> ('a -> string) -> ('b -> string) -> 'a * 'b -> string
 (** Print tuple in a string