diff --git a/skews.cabal b/skews.cabal
--- a/skews.cabal
+++ b/skews.cabal
@@ -1,5 +1,5 @@
 name:                skews
-version:             0.1.0.2
+version:             0.1.0.3
 synopsis:            A very quick-and-dirty WebSocket server.
 description:         A very quick-and-dirty WebSocket server. Intended for use with unit tests.
 homepage:            https://github.com/iij-ii/direct-hs/tree/master/skews
@@ -31,7 +31,7 @@
                      , async >= 2.1.1
                      , bytestring
                      , deque
-                     , envy
+                     , envy >= 2.0
                      , hspec
                      , network
                      , websockets
diff --git a/src/Network/WebSockets/Skews.hs b/src/Network/WebSockets/Skews.hs
--- a/src/Network/WebSockets/Skews.hs
+++ b/src/Network/WebSockets/Skews.hs
@@ -37,10 +37,9 @@
 import           Control.Applicative  ((<|>))
 import           Control.Concurrent   (ThreadId, forkIO)
 import           Control.Exception    (handleJust)
-import           Control.Monad        (mapM_)
 import qualified Data.ByteString.Lazy as B
 import qualified Data.IORef           as IOR
-import           Data.Monoid          (mempty)
+
 #if MIN_VERSION_deque(0, 3, 0)
 import qualified Deque.Lazy           as Q
 import           GHC.Exts             (fromList)
@@ -48,6 +47,7 @@
 import           Deque                (fromList)
 import qualified Deque                as Q
 #endif
+
 import qualified Network.WebSockets   as WS
 
 
diff --git a/test/Network/WebSockets/SkewsSpec.hs b/test/Network/WebSockets/SkewsSpec.hs
--- a/test/Network/WebSockets/SkewsSpec.hs
+++ b/test/Network/WebSockets/SkewsSpec.hs
@@ -29,14 +29,18 @@
 newtype PortNumber = PortNumber Int deriving (Eq, Show)
 
 instance FromEnv PortNumber where
+#if MIN_VERSION_envy(2, 0, 0)
+  fromEnv _ = do
+#else
   fromEnv = do
-    mpn <- (readMaybe <$> env "SKEWS_TEST_PORT") <|> pure (Just 8614)
+#endif
+    mpn <- (readMaybe <$> env "SKEWS_TEST_PORT") <|> pure (Just 8613)
     PortNumber <$> maybe empty pure mpn
 
 
 spec :: Spec
 spec = context "After running Skews.start and starting a client" $ do
-  PortNumber pn <- either fail return =<< runIO decodeEnv
+  PortNumber pn <- runIO $ either fail return =<< decodeEnv
 
   let host = "127.0.0.1"
   server <- runIO $ Skews.start $ Skews.Args host pn