diff --git a/src/Tiny_httpd.ml b/src/Tiny_httpd.ml
index 972f3ea2..4e859e91 100644
--- a/src/Tiny_httpd.ml
+++ b/src/Tiny_httpd.ml
@@ -181,7 +181,7 @@ module Byte_stream = struct
     )
 
   let to_chan (oc:out_channel) (self:t) =
-    iter (fun s i len -> Stdlib.output oc s i len) self
+    iter (fun s i len -> output oc s i len) self
 
   let of_bytes ?(i=0) ?len s : t =
     (* invariant: !i+!len is constant *)
@@ -762,14 +762,15 @@ end
 (* semaphore, for limiting concurrency. *)
 module Sem_ = struct
   type t = {
-    mutable n : int;
-    mutex : Mutex.t;
-    cond : Condition.t;
-  }
+      mutable n : int;
+      max:int;
+      mutex : Mutex.t;
+      cond : Condition.t;
+    }
 
   let create n =
     if n <= 0 then invalid_arg "Semaphore.create";
-    { n; mutex=Mutex.create(); cond=Condition.create(); }
+    { n; max=n; mutex=Mutex.create(); cond=Condition.create(); }
 
   let acquire m t =
     Mutex.lock t.mutex;
@@ -786,6 +787,9 @@ module Sem_ = struct
     t.n <- t.n + m;
     Condition.broadcast t.cond;
     Mutex.unlock t.mutex
+
+  let num_acquired self = self.max - self.n
+
 end
 
 module Route = struct
@@ -928,6 +932,10 @@ type t = {
 let addr self = self.addr
 let port self = self.port
 
+let active_connections self =
+  (* -1 because we decrease the semaphore before Unix.accept *)
+  Sem_.num_acquired self.sem_max_connections - 1
+
 let add_decode_request_cb self f =  self.cb_decode_req <- f :: self.cb_decode_req
 let add_encode_response_cb self f = self.cb_encode_resp <- f :: self.cb_encode_resp
 let set_top_handler self f = self.handler <- f
diff --git a/src/dune b/src/dune
index 26789fb1..29a2fb12 100644
--- a/src/dune
+++ b/src/dune
@@ -2,6 +2,6 @@
 (library
   (name tiny_httpd)
   (public_name tiny_httpd)
-  (libraries threads stdlib-shims)
+  (libraries threads)
   (flags :standard -safe-string -warn-error -a+8)
   (wrapped false))
diff --git a/tiny_httpd.opam b/tiny_httpd.opam
index f551c67f..8a0df3ff 100644
--- a/tiny_httpd.opam
+++ b/tiny_httpd.opam
@@ -11,7 +11,6 @@ build: [
 ]
 depends: [
   "dune" { >= "2.0" }
-  "stdlib-shims"
   "base-threads"
   "ocaml" { >= "4.04.0" }
   "odoc" {with-doc}