diff --git a/src/unix/lwt_io.ml b/src/unix/lwt_io.ml
index ec473df5d0..39f7c9ab5c 100644
--- a/src/unix/lwt_io.ml
+++ b/src/unix/lwt_io.ml
@@ -1486,7 +1486,7 @@ let shutdown_server_deprecated server =
 let establish_server_generic
     bind_function
     ?fd:preexisting_socket_for_listening
-    ?(backlog = Lwt_unix.somaxconn ())
+    ?(backlog = Lwt_unix.somaxconn () [@ocaml.warning "-3"])
     listening_address
     connection_handler_callback =
 
diff --git a/src/unix/lwt_unix.cppo.mli b/src/unix/lwt_unix.cppo.mli
index eb53464ce7..0afc83ae08 100644
--- a/src/unix/lwt_unix.cppo.mli
+++ b/src/unix/lwt_unix.cppo.mli
@@ -1534,4 +1534,4 @@ val has_wait4 : bool
   (** @deprecated Use [Lwt_sys.have `wait4]. *)
 
 val somaxconn : unit -> int
-  [@@ocaml.deprected " This is an internal function."]
+  [@@ocaml.deprecated " This is an internal function."]