diff --git a/dune-project b/dune-project
index 4b8f0c1..efa8994 100644
--- a/dune-project
+++ b/dune-project
@@ -29,7 +29,7 @@
    (and
     :with-test
     (>= 1.0.1)))
-  async
+  async_unix
   bignum
   ppx_jane
   (iter
diff --git a/mssql.opam b/mssql.opam
index 8780560..f2a1717 100644
--- a/mssql.opam
+++ b/mssql.opam
@@ -11,7 +11,7 @@ bug-reports: "https://github.com/arenadotio/ocaml-mssql/issues"
 depends: [
   "alcotest" {with-test & >= "1.0.1"}
   "alcotest-async" {with-test & >= "1.0.1"}
-  "async"
+  "async_unix"
   "bignum"
   "ppx_jane"
   "iter" {>= "1.2"}
diff --git a/src/async_helper.ml b/src/async_helper.ml
index 6a15f82..9c3cd3c 100644
--- a/src/async_helper.ml
+++ b/src/async_helper.ml
@@ -1,4 +1,4 @@
-open Async
+open Async_unix
 
 (* Run a function in async without the caller needing to keep track.
    If we're already in Async's main thread, just run it, otherwise
diff --git a/src/client.ml b/src/client.ml
index f25490c..9de019b 100644
--- a/src/client.ml
+++ b/src/client.ml
@@ -1,5 +1,6 @@
-open Core
-open Async
+open Core_kernel
+open Async_kernel
+open Async_unix
 open Freetds
 open Mssql_error
 
diff --git a/src/client.mli b/src/client.mli
index bb9de79..0741d15 100644
--- a/src/client.mli
+++ b/src/client.mli
@@ -1,4 +1,4 @@
-open Async
+open Async_kernel
 
 type t
 
diff --git a/src/dune b/src/dune
index 19698ea..3d5739d 100644
--- a/src/dune
+++ b/src/dune
@@ -9,7 +9,7 @@ let preprocess =
 let () = Jbuild_plugin.V1.send @@ {|
 (library
  (public_name mssql)
- (libraries core async freetds iter bignum logs text)
+ (libraries core_kernel async_unix freetds iter bignum logs text)
  (preprocess
   (pps ppx_jane |} ^ preprocess ^ {|)))
 
diff --git a/src/test.mli b/src/test.mli
index 964bfe8..52b84f8 100644
--- a/src/test.mli
+++ b/src/test.mli
@@ -1,4 +1,5 @@
 (** Exposes functions to help with tests that use Mssql *)
+open Async_kernel
 
 (** Mssql db connection with test credentials *)
-val with_conn : (Client.t -> 'a Async.Deferred.t) -> 'a Async.Deferred.t
+val with_conn : (Client.t -> 'a Deferred.t) -> 'a Deferred.t
diff --git a/test/test_mssql.ml b/test/test_mssql.ml
index e085c8b..188ab1f 100644
--- a/test/test_mssql.ml
+++ b/test/test_mssql.ml
@@ -1,6 +1,6 @@
 open Core
-open Poly
-open Async
+open Async_kernel
+open Async_unix
 module Row = Mssql.Row
 
 let test_select_and_convert () =