diff --git a/src/core/CCString.ml b/src/core/CCString.ml
index a651349b..84991e40 100644
--- a/src/core/CCString.ml
+++ b/src/core/CCString.ml
@@ -469,9 +469,14 @@ module Split = struct
   *)
 end
 
+[@@@ifge 4.04]
+[@@@else_]
+
 let split_on_char c s: _ list =
   Split.list_cpy ~drop:Split.no_drop ~by:(String.make 1 c) s
 
+[@@@endif]
+
 (*$= & ~printer:Q.Print.(list string)
   ["a"; "few"; "words"; "from"; "our"; "sponsors"] \
     (split_on_char ' ' "a few words from our sponsors")