diff --git a/Yesod/EmbeddedStatic.hs b/Yesod/EmbeddedStatic.hs
--- a/Yesod/EmbeddedStatic.hs
+++ b/Yesod/EmbeddedStatic.hs
@@ -90,11 +90,7 @@
             resp = case pathInfo req of
                             ("res":_) -> stApp site req
                             ("widget":_) -> staticApp (widgetSettings site) req
-#if MIN_VERSION_wai(3,0,0)
                             _ -> ($ responseLBS status404 [] "Not Found")
-#else
-                            _ -> return $ responseLBS status404 [] "Not Found"
-#endif
 
 -- | Create the haskell variable for the link to the entry
 mkRoute :: ComputedEntry -> Q [Dec]
diff --git a/Yesod/EmbeddedStatic/Internal.hs b/Yesod/EmbeddedStatic/Internal.hs
--- a/Yesod/EmbeddedStatic/Internal.hs
+++ b/Yesod/EmbeddedStatic/Internal.hs
@@ -107,11 +107,7 @@
     return $ ComputedEntry (ebHaskellName e) st link
 
 toApp :: (Request -> IO Response) -> Application
-#if MIN_VERSION_wai(3, 0, 0)
 toApp f req g = f req >>= g
-#else
-toApp = id
-#endif
 
 tryExtraDevelFiles :: [[T.Text] -> IO (Maybe (MimeType, BL.ByteString))] -> Application
 tryExtraDevelFiles = toApp . tryExtraDevelFiles'
@@ -133,19 +129,11 @@
 
 -- | Helper to create the development application at runtime
 develApp :: StaticSettings -> [[T.Text] -> IO (Maybe (MimeType, BL.ByteString))] -> Application
-#if MIN_VERSION_wai(3, 0, 0)
 develApp settings extra req sendResponse = do
     staticApp settings {ssMaxAge = NoMaxAge} req $ \resp ->
         if statusCode (responseStatus resp) == 404
             then tryExtraDevelFiles extra req sendResponse
             else sendResponse resp
-#else
-develApp settings extra req = do
-    resp <- staticApp settings {ssMaxAge = NoMaxAge} req
-    if statusCode (responseStatus resp) == 404
-        then tryExtraDevelFiles extra req
-        else return resp
-#endif
 
 -- | The type of 'addStaticContent'
 type AddStaticContent site = T.Text -> T.Text -> BL.ByteString
diff --git a/yesod-static.cabal b/yesod-static.cabal
--- a/yesod-static.cabal
+++ b/yesod-static.cabal
@@ -1,5 +1,5 @@
 name:            yesod-static
-version:         1.2.4
+version:         1.4.0
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>
@@ -27,7 +27,7 @@
     build-depends:   base                  >= 4        && < 5
                    , containers            >= 0.2
                    , old-time              >= 1.0
-                   , yesod-core            >= 1.2      && < 1.3
+                   , yesod-core            >= 1.4      && < 1.5
                    , base64-bytestring     >= 0.1.0.1
                    , byteable              >= 0.1
                    , bytestring            >= 0.9.1.4
@@ -80,7 +80,7 @@
     cpp-options:   -DTEST_EXPORT
     build-depends:   base
                    , hspec >= 1.3
-                   , yesod-test >= 1.2
+                   , yesod-test >= 1.4
                    , wai-test
                    , wai-extra
                    , HUnit