diff --git a/snap-server.cabal b/snap-server.cabal
--- a/snap-server.cabal
+++ b/snap-server.cabal
@@ -1,5 +1,5 @@
 name:           snap-server
-version:        0.9.4.0
+version:        0.9.4.1
 synopsis:       A fast, iteratee-based, epoll-enabled web server for the Snap Framework
 description:
   Snap is a simple and fast web development framework and server written in
@@ -91,7 +91,7 @@
     blaze-builder             >= 0.2.1.4  && < 0.4,
     blaze-builder-enumerator  >= 0.2.0    && < 0.3,
     bytestring                >= 0.9.1    && < 0.11,
-    case-insensitive          >= 0.3      && < 1.2,
+    case-insensitive          >= 0.3      && < 1.3,
     containers                >= 0.3      && < 0.6,
     enumerator                >= 0.4.15   && < 0.5,
     MonadCatchIO-transformers >= 0.2.1    && < 0.4,
diff --git a/src/Snap/Internal/Http/Server/Config.hs b/src/Snap/Internal/Http/Server/Config.hs
--- a/src/Snap/Internal/Http/Server/Config.hs
+++ b/src/Snap/Internal/Http/Server/Config.hs
@@ -97,7 +97,23 @@
     , proxyType      :: Maybe ProxyType
     , startupHook    :: Maybe (StartupInfo m a -> IO ())
     }
+#if MIN_VERSION_base(4,7,0)
+  deriving Typeable
+#else
 
+
+------------------------------------------------------------------------------
+-- | The 'Typeable1' instance is here so 'Config' values can be
+-- dynamically loaded with Hint.
+configTyCon :: TyCon
+configTyCon = mkTyCon "Snap.Http.Server.Config.Config"
+{-# NOINLINE configTyCon #-}
+
+instance (Typeable1 m) => Typeable1 (Config m) where
+    typeOf1 _ = mkTyConApp configTyCon [typeOf1 (undefined :: m ())]
+#endif
+
+
 instance Show (Config m a) where
     show c = unlines [ "Config:"
                      , "hostname: "       ++ _hostname
@@ -187,17 +203,6 @@
         }
       where
         ov f = getLast $! (mappend `on` (Last . f)) a b
-
-
-------------------------------------------------------------------------------
--- | The 'Typeable1' instance is here so 'Config' values can be
--- dynamically loaded with Hint.
-configTyCon :: TyCon
-configTyCon = mkTyCon "Snap.Http.Server.Config.Config"
-{-# NOINLINE configTyCon #-}
-
-instance (Typeable1 m) => Typeable1 (Config m) where
-    typeOf1 _ = mkTyConApp configTyCon [typeOf1 (undefined :: m ())]
 
 
 ------------------------------------------------------------------------------
diff --git a/src/Snap/Internal/Http/Server/Date.hs b/src/Snap/Internal/Http/Server/Date.hs
--- a/src/Snap/Internal/Http/Server/Date.hs
+++ b/src/Snap/Internal/Http/Server/Date.hs
@@ -62,7 +62,7 @@
 
 ------------------------------------------------------------------------------
 ensureFreshDate :: IO ()
-ensureFreshDate = block $ do
+ensureFreshDate = mask $ \_ -> do
     now <- epochTime
     old <- readIORef $ _lastFetchTime dateState
     when (now > old) $ updateState dateState
@@ -70,14 +70,14 @@
 
 ------------------------------------------------------------------------------
 getDateString :: IO ByteString
-getDateString = block $ do
+getDateString = mask $ \_ -> do
     ensureFreshDate
     readIORef $ _cachedDateString dateState
 
 
 ------------------------------------------------------------------------------
 getLogDateString :: IO ByteString
-getLogDateString = block $ do
+getLogDateString = mask $ \_ -> do
     ensureFreshDate
     readIORef $ _cachedLogString dateState
 
diff --git a/src/Snap/Internal/Http/Server/SimpleBackend.hs b/src/Snap/Internal/Http/Server/SimpleBackend.hs
--- a/src/Snap/Internal/Http/Server/SimpleBackend.hs
+++ b/src/Snap/Internal/Http/Server/SimpleBackend.hs
@@ -24,7 +24,11 @@
 import           Data.Maybe
 import           Foreign hiding (new)
 import           Foreign.C
+#if MIN_VERSION_base(4,4,0)
+import           GHC.Conc (labelThread, forkOn)
+#else
 import           GHC.Conc (labelThread, forkOnIO)
+#endif
 import           Network.Socket
 #if !MIN_VERSION_base(4,6,0)
 import           Prelude hiding (catch)
@@ -47,6 +51,13 @@
 
 
 ------------------------------------------------------------------------------
+#if !MIN_VERSION_base(4,4,0)
+forkOn :: Int -> IO () -> IO ThreadId
+forkOn = forkOnIO
+#endif
+
+
+------------------------------------------------------------------------------
 -- | For each cpu, we store:
 --    * A list of accept threads, one per port.
 --    * A TimeoutManager
@@ -85,15 +96,14 @@
 newLoop defaultTimeout sockets handler elog cpu = do
     tmgr       <- TM.initialize defaultTimeout getCurrentDateTime
     exit       <- newEmptyMVar
-    accThreads <- forM sockets $ \p -> forkOnIO cpu $
+    accThreads <- forM sockets $ \p -> forkOn cpu $
                   acceptThread defaultTimeout handler tmgr elog cpu p exit
 
     return $! EventLoopCpu cpu accThreads tmgr exit
 
-
 ------------------------------------------------------------------------------
 stopLoop :: EventLoopCpu -> IO ()
-stopLoop loop = block $ do
+stopLoop loop = mask $ \_ -> do
     TM.stop $ _timeoutManager loop
     Prelude.mapM_ killThread $ _acceptThreads loop
 
@@ -115,7 +125,7 @@
         (s,addr) <- accept $ Listen.listenSocket sock
         setSocketOption s NoDelay 1
         debug $ "acceptThread: accepted connection from remote: " ++ show addr
-        _ <- forkOnIO cpu (go s addr `catches` cleanup)
+        _ <- forkOn cpu (go s addr `catches` cleanup)
         return ()
 
     loop = do
@@ -169,7 +179,7 @@
 
     bracket (Listen.createSession lsock 8192 fd
               (threadWaitRead $ fromIntegral fd))
-            (\session -> block $ do
+            (\session -> mask $ \_ -> do
                  debug "thread killed, closing socket"
 
                  -- cancel thread timeout
diff --git a/test/snap-server-testsuite.cabal b/test/snap-server-testsuite.cabal
--- a/test/snap-server-testsuite.cabal
+++ b/test/snap-server-testsuite.cabal
@@ -159,7 +159,7 @@
     blaze-builder              >= 0.2.1.4  && <0.4,
     blaze-builder-enumerator   >= 0.2.0    && <0.3,
     bytestring,
-    case-insensitive           >= 0.3      && <1.2,
+    case-insensitive           >= 0.3      && <1.3,
     containers,
     directory-tree,
     enumerator                 >= 0.4.15   && <0.5,