diff --git a/dune-project b/dune-project
index 9e0b44e7f..0496f7267 100644
--- a/dune-project
+++ b/dune-project
@@ -18,8 +18,8 @@
  (depends
   (ocaml (>= 4.08.1))
   (camlzip (>= 1.04))
-  (cohttp-lwt-unix (and (>= 5.0) (< 6.0)))
-  (conduit-lwt-unix (and (>= 2.0) (< 7.0)))
+  (cohttp-lwt-unix (>= 6.0))
+  conduit-lwt-unix
   http
   cryptokit
   (ipaddr (>= 2.1))
diff --git a/ocsigenserver.opam b/ocsigenserver.opam
index ef989a6dd..130baa5a2 100644
--- a/ocsigenserver.opam
+++ b/ocsigenserver.opam
@@ -13,8 +13,8 @@ depends: [
   "dune" {>= "3.19"}
   "ocaml" {>= "4.08.1"}
   "camlzip" {>= "1.04"}
-  "cohttp-lwt-unix" {>= "5.0" & < "6.0"}
-  "conduit-lwt-unix" {>= "2.0" & < "7.0"}
+  "cohttp-lwt-unix" {>= "6.0"}
+  "conduit-lwt-unix"
   "http"
   "cryptokit"
   "ipaddr" {>= "2.1"}
diff --git a/src/extensions/deflatemod.ml b/src/extensions/deflatemod.ml
index 2ca4adfe5..380cd4d78 100644
--- a/src/extensions/deflatemod.ml
+++ b/src/extensions/deflatemod.ml
@@ -205,8 +205,9 @@ let stream_filter contentencoding url deflate choice res =
                | None, _ | _, None -> Lwt.return res
                | Some a, Some b when should_compress (a, b) url choice ->
                    let response =
-                     let response = Ocsigen_response.response res in
-                     let headers = Cohttp.Response.headers response in
+                     let {Http.Response.headers; status; version} =
+                       Ocsigen_response.response res
+                     in
                      let headers =
                        let name = Ocsigen_header.Name.(to_string etag) in
                        match Cohttp.Header.get headers name with
@@ -217,13 +218,11 @@ let stream_filter contentencoding url deflate choice res =
                        | None -> headers
                      in
                      let headers =
-                       Cohttp.Header.replace headers
+                       Http.Header.replace headers
                          Ocsigen_header.Name.(to_string content_encoding)
                          contentencoding
                      in
-                     { response with
-                       Cohttp.Response.headers
-                     ; Cohttp.Response.encoding = Cohttp.Transfer.Chunked }
+                     Http.Response.make ~headers ~status ~version ()
                    and body =
                      Ocsigen_response.Body.make Cohttp.Transfer.Chunked
                        (compress_body deflate
diff --git a/src/server/ocsigen_cohttp.ml b/src/server/ocsigen_cohttp.ml
index cd152f01f..086984041 100644
--- a/src/server/ocsigen_cohttp.ml
+++ b/src/server/ocsigen_cohttp.ml
@@ -155,8 +155,6 @@ let handler ~ssl ~address ~port ~connector (flow, conn) request body =
 
 let conn_closed (_flow, conn) =
   try
-    Logs.debug ~src:section (fun fmt ->
-      fmt "Connection closed:\n%s" (Cohttp.Connection.to_string conn));
     Lwt.wakeup (snd (Hashtbl.find connections conn)) ();
     Hashtbl.remove connections conn;
     decr_connected ()
diff --git a/src/server/ocsigen_response.ml b/src/server/ocsigen_response.ml
index d9e5fe7d2..7bfdb8449 100644
--- a/src/server/ocsigen_response.ml
+++ b/src/server/ocsigen_response.ml
@@ -53,7 +53,8 @@ let respond_error ?headers ?(status = `Internal_server_error) ~body () =
 let update ?response ?body ?cookies {a_response; a_body; a_cookies} =
   let a_response =
     match response with Some response -> response | None -> a_response
-  and a_body = match body with Some body -> body | None -> a_body
+  in
+  let a_body = match body with Some body -> body | None -> a_body
   and a_cookies =
     match cookies with Some cookies -> cookies | None -> a_cookies
   in
@@ -90,19 +91,25 @@ let make_cookies_headers path t hds =
          (make_cookies_header path exp name v secure))
     t hds
 
-let to_cohttp_response {a_response; a_cookies; a_body = _} =
+let to_cohttp_response {a_response; a_cookies; a_body = _, encoding} =
   let headers =
     let add name value headers = Header.add_unless_exists headers name value in
+    let add_transfer_encoding h =
+      match encoding with
+      | Transfer.Chunked -> add "transfer-encoding" "chunked" h
+      | _ -> h
+    in
     Ocsigen_cookie_map.Map_path.fold make_cookies_headers a_cookies
       (Response.headers a_response)
     |> add "server" Ocsigen_config.server_name
     |> add "date" (Ocsigen_lib.Date.to_string (Unix.time ()))
+    |> add_transfer_encoding
   in
   {a_response with Response.headers}
 
 let to_response_expert t =
   let module R = Cohttp_lwt_unix.Response in
-  let write_footer {R.encoding; _} oc =
+  let write_footer encoding oc =
     (* Copied from [cohttp/response.ml]. *)
     match encoding with
     | Transfer.Chunked -> Lwt_io.write oc "0\r\n\r\n"
@@ -112,8 +119,9 @@ let to_response_expert t =
   ( res
   , fun _ic oc ->
       let writer = R.make_body_writer ~flush:false res oc in
-      let* () = fst t.a_body (R.write_body writer) in
-      write_footer res oc )
+      let body, encoding = t.a_body in
+      let* () = body (R.write_body writer) in
+      write_footer encoding oc )
 
 let response t = t.a_response
 let body t = t.a_body
diff --git a/test/extensions/deflatemod.t/run.t b/test/extensions/deflatemod.t/run.t
index b72a88677..56c8efe4f 100644
--- a/test/extensions/deflatemod.t/run.t
+++ b/test/extensions/deflatemod.t/run.t
@@ -21,8 +21,8 @@ First response is not compressed:
   $ curl_ "index.html"
   HTTP/1.1 200 OK
   content-type: text/html
-  server: Ocsigen
   content-length: 12
+  server: Ocsigen
   
   Hello world
 
@@ -31,6 +31,7 @@ Second response is compressed:
   $ curl_ "index.html" --compressed
   HTTP/1.1 200 OK
   content-type: text/html
+  content-length: 12
   content-encoding: gzip
   server: Ocsigen
   transfer-encoding: chunked