diff --git a/Network/Wai/Application/Classic/Def.hs b/Network/Wai/Application/Classic/Def.hs
--- a/Network/Wai/Application/Classic/Def.hs
+++ b/Network/Wai/Application/Classic/Def.hs
@@ -4,11 +4,11 @@
 
 import Control.Applicative
 import Control.Exception
+import Data.ByteString (ByteString)
 import Network.HTTP.Date
 import Network.Wai.Application.Classic.Path
 import Network.Wai.Application.Classic.Types
 import Network.Wai.Logger
-import System.Log.FastLogger.Date
 import System.Posix
 
 -- |
@@ -24,7 +24,7 @@
 defaultLogger :: ApacheLogger
 defaultLogger _ _ _ = return ()
 
-defaultDater :: IO ZonedDate
+defaultDater :: IO ByteString
 defaultDater = formatHTTPDate . epochTimeToHTTPDate <$> epochTime
 
 ----------------------------------------------------------------
diff --git a/Network/Wai/Application/Classic/Types.hs b/Network/Wai/Application/Classic/Types.hs
--- a/Network/Wai/Application/Classic/Types.hs
+++ b/Network/Wai/Application/Classic/Types.hs
@@ -8,7 +8,6 @@
 import Network.HTTP.Types
 import Network.Wai.Application.Classic.Path
 import Network.Wai.Logger
-import System.Log.FastLogger
 #ifdef REV_PROXY
 import qualified Network.HTTP.Conduit as H
 #endif
@@ -20,8 +19,9 @@
     softwareName :: ByteString
     -- | A function for logging. The third argument is a body size.
   , logger :: ApacheLogger
+    -- | A function to get HTTP's GMT Date.
+  , dater :: IO ByteString
     -- | A function to get the HTTP body of status.
-  , dater :: IO ZonedDate
   , statusFileDir :: Path
   }
 
diff --git a/wai-app-file-cgi.cabal b/wai-app-file-cgi.cabal
--- a/wai-app-file-cgi.cabal
+++ b/wai-app-file-cgi.cabal
@@ -1,5 +1,5 @@
 Name:                   wai-app-file-cgi
-Version:                0.8.4
+Version:                0.8.5
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -51,7 +51,6 @@
                       , containers
                       , date-cache
                       , directory
-                      , fast-logger >= 0.3
                       , filepath
                       , http-date
                       , http-types >= 0.7