diff --git a/Network/Wai/Application/Static.hs b/Network/Wai/Application/Static.hs
--- a/Network/Wai/Application/Static.hs
+++ b/Network/Wai/Application/Static.hs
@@ -193,35 +193,35 @@
 staticApp set req = staticAppPieces set (W.pathInfo req) req
 
 staticAppPieces :: StaticSettings -> [Text] -> W.Application
-staticAppPieces _ _ req
-    | W.requestMethod req /= "GET" = return $ W.responseLBS
+staticAppPieces _ _ req sendResponse
+    | W.requestMethod req /= "GET" = sendResponse $ W.responseLBS
         H.status405
         [("Content-Type", "text/plain")]
         "Only GET is supported"
-staticAppPieces _ [".hidden", "folder.png"] _  = return $ W.responseLBS H.status200 [("Content-Type", "image/png")] $ L.fromChunks [$(embedFile "images/folder.png")]
-staticAppPieces _ [".hidden", "haskell.png"] _ = return $ W.responseLBS H.status200 [("Content-Type", "image/png")] $ L.fromChunks [$(embedFile "images/haskell.png")]
-staticAppPieces ss rawPieces req = liftIO $ do
+staticAppPieces _ [".hidden", "folder.png"] _ sendResponse = sendResponse $ W.responseLBS H.status200 [("Content-Type", "image/png")] $ L.fromChunks [$(embedFile "images/folder.png")]
+staticAppPieces _ [".hidden", "haskell.png"] _ sendResponse = sendResponse $ W.responseLBS H.status200 [("Content-Type", "image/png")] $ L.fromChunks [$(embedFile "images/haskell.png")]
+staticAppPieces ss rawPieces req sendResponse = liftIO $ do
     case toPieces rawPieces of
         Just pieces -> checkPieces ss pieces req >>= response
-        Nothing -> return $ W.responseLBS H.status403
+        Nothing -> sendResponse $ W.responseLBS H.status403
             [ ("Content-Type", "text/plain")
             ] "Forbidden"
   where
-    response :: StaticResponse -> IO W.Response
+    response :: StaticResponse -> IO W.ResponseReceived
     response (FileResponse file ch) = do
         mimetype <- ssGetMimeType ss file
         let filesize = fileGetSize file
         let headers = ("Content-Type", mimetype)
                     : ("Content-Length", S8.pack $ show filesize)
                     : ch
-        return $ fileToResponse file H.status200 headers
+        sendResponse $ fileToResponse file H.status200 headers
 
     response NotModified =
-            return $ W.responseLBS H.status304 [] ""
+            sendResponse $ W.responseLBS H.status304 [] ""
 
     response (SendContent mt lbs) = do
             -- TODO: set caching headers
-            return $ W.responseLBS H.status200
+            sendResponse $ W.responseLBS H.status200
                 [ ("Content-Type", mt)
                   -- TODO: set Content-Length
                 ] lbs
@@ -232,13 +232,13 @@
                   Just hash -> replace "etag" (Just hash) (W.queryString req)
                   Nothing   -> remove "etag" (W.queryString req)
 
-            return $ W.responseLBS H.status301
+            sendResponse $ W.responseLBS H.status301
                 [ ("Content-Type", "text/plain")
                 , ("Location", S8.append loc $ H.renderQuery True qString)
                 ] "Redirect"
 
-    response NotFound = return $ W.responseLBS H.status404
+    response NotFound = sendResponse $ W.responseLBS H.status404
                         [ ("Content-Type", "text/plain")
                         ] "File not found"
 
-    response (WaiResponse r) = return r
+    response (WaiResponse r) = sendResponse r
diff --git a/WaiAppStatic/CmdLine.hs b/WaiAppStatic/CmdLine.hs
--- a/WaiAppStatic/CmdLine.hs
+++ b/WaiAppStatic/CmdLine.hs
@@ -38,12 +38,6 @@
     , host :: String
     }
 
-#if MIN_VERSION_optparse_applicative(0, 10, 0)
-option' = option auto
-#else
-option' = option
-#endif
-
 args :: Parser Args
 args = Args
     <$> strOption
@@ -58,7 +52,7 @@
            <> metavar "INDEX"
            <> help "index files to serve when a directory is required"
             )))
-    <*> option'
+    <*> option
             ( long "port"
            <> short 'p'
            <> metavar "PORT"
diff --git a/wai-app-static.cabal b/wai-app-static.cabal
--- a/wai-app-static.cabal
+++ b/wai-app-static.cabal
@@ -1,5 +1,5 @@
 name:            wai-app-static
-version:         2.0.1.1
+version:         3.0.0
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>
@@ -24,7 +24,7 @@
 
 library
     build-depends:   base                      >= 4        && < 5
-                   , wai                       >= 2.0      && < 2.2
+                   , wai                       >= 3.0      && < 3.1
                    , bytestring                >= 0.9.1.4
                    , http-types                >= 0.7
                    , transformers              >= 0.2.2
@@ -39,7 +39,6 @@
                    , base64-bytestring         >= 0.1
                    , byteable
                    , cryptohash                >= 0.11
-                   , cryptohash-conduit        >= 0.1.0
                    , system-filepath           >= 0.4
                    , system-fileio             >= 0.3
                    , http-date
@@ -50,9 +49,11 @@
                    , template-haskell          >= 2.7
                    , zlib                      >= 0.5
                    , filepath
-                   , wai-extra                 >= 2.0      && < 2.2
+                   , wai-extra                 >= 3.0      && < 3.1
                    , optparse-applicative      >= 0.7
-                   , warp                      >= 2.0      && < 2.2
+                   , warp                      >= 3.0      && < 3.1
+                   -- Used exclusively for hashFile function
+                   , cryptohash-conduit
 
     exposed-modules: Network.Wai.Application.Static
                      WaiAppStatic.Storage.Filesystem
@@ -73,7 +74,7 @@
   Main-is:        warp-static.hs
   hs-source-dirs: app
   Build-depends: base            >= 4                  && < 5
-               , wai-app-static  >= 2.0                && < 2.1
+               , wai-app-static
                , directory       >= 1.0
                , containers      >= 0.2
                , bytestring      >= 0.9.1.4
@@ -91,8 +92,8 @@
                    , time
                    , old-locale
                    , http-date
-                   , wai-app-static            >= 1.3
-                   , wai-test
+                   , wai-app-static
+                   , wai-extra
                    , wai
                    , http-types
                    , network