diff --git a/.travis.yml b/.travis.yml
index 18e1e2ece5..0dcc7ae242 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,30 +10,28 @@ env:
   matrix:
   - PACKAGE="cohttp" DISTRO="ubuntu-lts" OCAML_VERSION="4.08" DEPOPTS="cohttp-async cohttp-lwt-unix cohttp-mirage"
   - PACKAGE="cohttp" DISTRO="ubuntu-lts" OCAML_VERSION="4.07"
-  - PACKAGE="cohttp-async" DISTRO="ubuntu-lts" OCAML_VERSION="4.07"
+  - PACKAGE="cohttp-async" DISTRO="ubuntu-lts" OCAML_VERSION="4.08"
+  - PACKAGE="cohttp-async" DISTRO="alpine" OCAML_VERSION="4.08"
+  - PACKAGE="cohttp-async" DISTRO="debian-unstable" OCAML_VERSION="4.08"
+  - PACKAGE="cohttp-async" DISTRO="ubuntu-16.04" OCAML_VERSION="4.08"
   - PACKAGE="cohttp-lwt-unix" DISTRO="ubuntu-lts" OCAML_VERSION="4.07"
   - PACKAGE="cohttp-lwt-jsoo" DISTRO="ubuntu-lts" OCAML_VERSION="4.07"
   - PACKAGE="cohttp-lwt" DISTRO="ubuntu-lts" OCAML_VERSION="4.07"
   - PACKAGE="cohttp-mirage" DISTRO="alpine" OCAML_VERSION="4.07"
   - PACKAGE="cohttp" DISTRO="alpine" OCAML_VERSION="4.06"
-  - PACKAGE="cohttp-async" DISTRO="alpine" OCAML_VERSION="4.06"
   - PACKAGE="cohttp-lwt-unix" DISTRO="alpine" OCAML_VERSION="4.06"
   - PACKAGE="cohttp-lwt-jsoo" DISTRO="alpine" OCAML_VERSION="4.06"
   - PACKAGE="cohttp-lwt" DISTRO="alpine" OCAML_VERSION="4.06"
   - PACKAGE="cohttp" DISTRO="debian-unstable" OCAML_VERSION="4.05"
-  - PACKAGE="cohttp-async" DISTRO="debian-unstable" OCAML_VERSION="4.05"
   - PACKAGE="cohttp-lwt-unix" DISTRO="debian-unstable" OCAML_VERSION="4.05"
   - PACKAGE="cohttp-lwt-jsoo" DISTRO="debian-unstable" OCAML_VERSION="4.05"
   - PACKAGE="cohttp-lwt" DISTRO="debian-unstable" OCAML_VERSION="4.05"
   - PACKAGE="cohttp" DISTRO="ubuntu-16.04" OCAML_VERSION="4.04"
-  - PACKAGE="cohttp-async" DISTRO="ubuntu-16.04" OCAML_VERSION="4.04"
   - PACKAGE="cohttp-lwt-unix" DISTRO="ubuntu-16.04" OCAML_VERSION="4.04"
   - PACKAGE="cohttp-lwt-jsoo" DISTRO="ubuntu-16.04" OCAML_VERSION="4.04"
   - PACKAGE="cohttp-lwt" DISTRO="ubuntu-16.04" OCAML_VERSION="4.04"
 matrix:
   allow_failures:
-  - env: PACKAGE="cohttp-async" DISTRO="alpine" OCAML_VERSION="4.06"
-  - env: PACKAGE="cohttp-async" DISTRO="debian-unstable" OCAML_VERSION="4.05"
   - env: PACKAGE="cohttp-lwt-unix" DISTRO="debian-unstable" OCAML_VERSION="4.05"
 
 notifications:
diff --git a/cohttp-async.opam b/cohttp-async.opam
index 3df9fad831..ca68676306 100644
--- a/cohttp-async.opam
+++ b/cohttp-async.opam
@@ -25,9 +25,9 @@ bug-reports: "https://github.com/mirage/ocaml-cohttp/issues"
 depends: [
   "ocaml" {>= "4.04.1"}
   "dune" {>= "1.1.0"}
-  "async_kernel" {>= "v0.11.0"}
-  "async_unix" {>= "v0.11.0"}
-  "async_extra" {>= "v0.11.0"}
+  "async_kernel" {>= "v0.13.0"}
+  "async_unix" {>= "v0.13.0"}
+  "async" {>= "v0.13.0"}
   "base" {>= "v0.11.0"}
   "core" {with-test}
   "cohttp" {=version}
@@ -37,7 +37,7 @@ depends: [
   "fmt" {>= "0.8.2"}
   "sexplib0"
   "stdlib-shims"
-  "ppx_sexp_conv" {>= "v0.9.0"}
+  "ppx_sexp_conv" {>= "v0.13.0"}
   "ounit" {with-test}
   "uri" {>= "2.0.0"}
   "uri-sexp"
diff --git a/cohttp-async/bin/cohttp_curl_async.ml b/cohttp-async/bin/cohttp_curl_async.ml
index 0b80bfac43..cd634f945b 100644
--- a/cohttp-async/bin/cohttp_curl_async.ml
+++ b/cohttp-async/bin/cohttp_curl_async.ml
@@ -38,7 +38,7 @@ let _ =
   Fmt_tty.setup_std_outputs ();
   Logs.set_level @@ Some Logs.Debug;
   Logs.set_reporter (Logs_fmt.reporter ());
-  let open Async_extra.Command in
+  let open Async_command in
   async_spec ~summary:"Fetch URL and print it"
     Spec.(
       empty
diff --git a/cohttp-async/bin/cohttp_server_async.ml b/cohttp-async/bin/cohttp_server_async.ml
index b544a0b937..f7cb243163 100644
--- a/cohttp-async/bin/cohttp_server_async.ml
+++ b/cohttp-async/bin/cohttp_server_async.ml
@@ -121,12 +121,12 @@ let start_server docroot port index cert_file key_file verbose () =
         Logs.err (fun f -> f "Error from %s" (Socket.Address.to_string addr));
         Logs.err (fun f -> f "%s" @@ Exn.to_string exn)))
     ~mode
-    (Async_extra.Tcp.Where_to_listen.of_port port)
+    (Tcp.Where_to_listen.of_port port)
     (handler ~info ~docroot ~index) >>= fun _serv ->
   Deferred.never ()
 
 let () =
-  let open Async_extra.Command in
+  let open Async_command in
   run @@
   async_spec ~summary:"Serve the local directory contents via HTTP or HTTPS"
     Spec.(
diff --git a/cohttp-async/bin/dune b/cohttp-async/bin/dune
index 43207b71e2..5c06d2b461 100644
--- a/cohttp-async/bin/dune
+++ b/cohttp-async/bin/dune
@@ -2,5 +2,5 @@
  (names         cohttp_curl_async cohttp_server_async)
   (package      cohttp-async)
   (public_names cohttp-curl-async cohttp-server-async)
-  (libraries    cohttp-async async_kernel async_extra async_unix base
+  (libraries    cohttp-async async_kernel async.async_command async_unix base
                 cohttp cohttp_server fmt.tty))
diff --git a/cohttp-async/src/dune b/cohttp-async/src/dune
index e772076216..1b2500a30f 100644
--- a/cohttp-async/src/dune
+++ b/cohttp-async/src/dune
@@ -2,6 +2,6 @@
   (name        cohttp_async)
   (synopsis    "Async backend")
   (public_name cohttp-async)
-  (libraries   logs.fmt base fmt async_unix async_kernel async_extra uri
+  (libraries   logs.fmt base fmt async_unix async_kernel uri
                uri.services uri-sexp ipaddr.unix conduit-async magic-mime cohttp)
   (preprocess (pps ppx_sexp_conv)))
diff --git a/cohttp-async/src/server.ml b/cohttp-async/src/server.ml
index 9f4069e544..4e53317b1d 100644
--- a/cohttp-async/src/server.ml
+++ b/cohttp-async/src/server.ml
@@ -1,7 +1,6 @@
 open Base
 open Async_kernel
 open Async_unix
-open Async_extra
 
 module Request = struct
   include Cohttp.Request
@@ -14,7 +13,7 @@ module Response = struct
 end
 
 type ('address, 'listening_on) t = {
-  server: ('address, 'listening_on) Tcp.Server.t sexp_opaque;
+  server: ('address, 'listening_on) Tcp.Server.t [@sexp.opaque];
 } [@@deriving sexp_of]
 
 type response = Response.t * Body.t [@@deriving sexp_of]
diff --git a/cohttp-async/src/server.mli b/cohttp-async/src/server.mli
index ebc584a386..17b606870e 100644
--- a/cohttp-async/src/server.mli
+++ b/cohttp-async/src/server.mli
@@ -74,7 +74,7 @@ val create_expert :
   on_handler_error:[ `Call of 'address -> exn  -> unit
                    | `Ignore
                    | `Raise ] ->
-  ('address, 'listening_on) Async_extra.Tcp.Where_to_listen.t
+  ('address, 'listening_on) Async.Tcp.Where_to_listen.t
   -> (body:Body.t -> 'address -> Request.t
       -> response_action Async_kernel.Deferred.t)
   -> ('address, 'listening_on) t Async_kernel.Deferred.t
@@ -89,6 +89,6 @@ val create :
   on_handler_error:[ `Call of 'address -> exn  -> unit
                    | `Ignore
                    | `Raise ] ->
-  ('address, 'listening_on) Async_extra.Tcp.Where_to_listen.t
+  ('address, 'listening_on) Async.Tcp.Where_to_listen.t
   -> (body:Body.t -> 'address -> Request.t -> response Async_kernel.Deferred.t)
   -> ('address, 'listening_on) t Async_kernel.Deferred.t
diff --git a/cohttp-lwt.opam b/cohttp-lwt.opam
index 7105d7f34e..ada5ae61f8 100644
--- a/cohttp-lwt.opam
+++ b/cohttp-lwt.opam
@@ -30,7 +30,7 @@ depends: [
   "cohttp" {=version}
   "lwt" {>= "2.5.0"}
   "sexplib0"
-  "ppx_sexp_conv" {>= "v0.9.0"}
+  "ppx_sexp_conv" {>= "v0.13.0"}
   "logs"
 ]
 build: [
diff --git a/cohttp-lwt/src/body.ml b/cohttp-lwt/src/body.ml
index 037500f3a2..0550280066 100644
--- a/cohttp-lwt/src/body.ml
+++ b/cohttp-lwt/src/body.ml
@@ -16,11 +16,10 @@
 
 open Cohttp
 open Lwt
-open Sexplib0.Sexp_conv
 
 type t = [
   | Body.t
-  | `Stream of string Lwt_stream.t sexp_opaque
+  | `Stream of (string Lwt_stream.t [@sexp.opaque])
 ] [@@deriving sexp]
 
 let empty = (Body.empty :> t)
diff --git a/cohttp.opam b/cohttp.opam
index 7f1ab64c02..a4df15e1cb 100644
--- a/cohttp.opam
+++ b/cohttp.opam
@@ -40,7 +40,7 @@ depends: [
   "fieldslib"
   "sexplib0"
   "ppx_fields_conv" {>= "v0.9.0"}
-  "ppx_sexp_conv" {>= "v0.9.0"}
+  "ppx_sexp_conv" {>= "v0.13.0"}
   "stringext"
   "base64" {>= "3.1.0"}
   "stdlib-shims"
diff --git a/cohttp_async_test/src/cohttp_async_test.ml b/cohttp_async_test/src/cohttp_async_test.ml
index d66c7ccd9e..b40fe0e628 100644
--- a/cohttp_async_test/src/cohttp_async_test.ml
+++ b/cohttp_async_test/src/cohttp_async_test.ml
@@ -29,7 +29,7 @@ let temp_server ?port spec callback =
     | Some p -> p in
   let uri = Uri.of_string ("http://0.0.0.0:" ^ (Int.to_string port)) in
   let server = Server.create_expert ~on_handler_error:`Raise
-    (Async_extra.Tcp.Where_to_listen.of_port port)
+    (Async.Tcp.Where_to_listen.of_port port)
     (fun ~body _sock req -> spec req body) in
   server >>= fun server ->
   callback uri >>= fun res ->
diff --git a/cohttp_async_test/src/dune b/cohttp_async_test/src/dune
index a359c44735..0c77334d59 100644
--- a/cohttp_async_test/src/dune
+++ b/cohttp_async_test/src/dune
@@ -1,5 +1,4 @@
 (library
   (name    cohttp_async_test)
   (wrapped false)
-  (libraries fmt.tty uri.services async_kernel async_extra cohttp_test
-             cohttp-async))
+  (libraries fmt.tty uri.services async_kernel cohttp_test cohttp-async))
diff --git a/examples/async/dune b/examples/async/dune
index 7ffe849e58..78c2522519 100644
--- a/examples/async/dune
+++ b/examples/async/dune
@@ -1,6 +1,6 @@
 (executables
   (names     hello_world receive_post)
-  (libraries cohttp-async async_extra base async_kernel))
+  (libraries cohttp-async base async_kernel))
 
 (alias
   (name    runtest)
diff --git a/examples/async/hello_world.ml b/examples/async/hello_world.ml
index 19dd4ec9ef..b566fb6646 100644
--- a/examples/async/hello_world.ml
+++ b/examples/async/hello_world.ml
@@ -23,11 +23,11 @@ let start_server port () =
   Caml.Printf.eprintf "Listening for HTTP on port %d\n" port;
   Caml.Printf.eprintf "Try 'curl http://localhost:%d/test?hello=xyz'\n%!" port;
   Cohttp_async.Server.create ~on_handler_error:`Raise
-    (Async_extra.Tcp.Where_to_listen.of_port port) handler
+    (Async.Tcp.Where_to_listen.of_port port) handler
   >>= fun _ -> Deferred.never ()
 
 let () =
-  let module Command = Async_extra.Command in
+  let module Command = Async_command in
   Command.async_spec
     ~summary:"Start a hello world Async server"
     Command.Spec.(
diff --git a/examples/async/receive_post.ml b/examples/async/receive_post.ml
index f5ff5bd2e0..91ef78b918 100644
--- a/examples/async/receive_post.ml
+++ b/examples/async/receive_post.ml
@@ -9,7 +9,7 @@ let start_server port () =
   Caml.Printf.eprintf "Listening for HTTP on port %d\n" port;
   Caml.Printf.eprintf "Try 'curl -X POST -d 'foo bar' http://localhost:%d\n" port;
   Cohttp_async.Server.create ~on_handler_error:`Raise
-    (Async_extra.Tcp.Where_to_listen.of_port port) (fun ~body _ req ->
+    (Async.Tcp.Where_to_listen.of_port port) (fun ~body _ req ->
       match req |> Cohttp.Request.meth with
       | `POST ->
         (Body.to_string body) >>= (fun body ->
@@ -20,7 +20,7 @@ let start_server port () =
   >>= fun _ -> Deferred.never ()
 
 let () =
-  let module Command = Async_extra.Command in
+  let module Command = Async_command in
   Command.async_spec
     ~summary:"Simple http server that outputs body of POST's"
     Command.Spec.(empty +>