diff --git a/Network/HTTP/ReverseProxy.hs b/Network/HTTP/ReverseProxy.hs
--- a/Network/HTTP/ReverseProxy.hs
+++ b/Network/HTTP/ReverseProxy.hs
@@ -22,18 +22,20 @@
     , waiToRaw
     ) where
 
-import ClassyPrelude
+import BasicPrelude
 import Data.Conduit
 import qualified Network.Wai as WAI
 import qualified Network.HTTP.Conduit as HC
 import Control.Exception.Lifted (try, finally)
 import Blaze.ByteString.Builder (fromByteString, flush)
 import Data.Word8 (isSpace, _colon, toLower, _cr)
+import qualified Data.ByteString as S
 import qualified Data.ByteString.Char8 as S8
 import qualified Network.HTTP.Types as HT
 import qualified Data.CaseInsensitive as CI
 import qualified Data.Text.Encoding as TE
 import qualified Data.Text.Lazy.Encoding as TLE
+import qualified Data.Text.Lazy as TL
 import qualified Data.Conduit.Network as DCN
 import Control.Concurrent.MVar.Lifted (newEmptyMVar, putMVar, takeMVar)
 import Control.Concurrent.Lifted (fork, killThread)
@@ -47,6 +49,7 @@
 import qualified Paths_http_reverse_proxy
 import Network.Wai.Logger.Utils (showSockAddr)
 import Blaze.ByteString.Builder (Builder)
+import qualified Data.Set as Set
 
 -- | Host\/port combination to which we want to proxy.
 data ProxyDest = ProxyDest
@@ -103,7 +106,7 @@
 defaultOnExc exc _ = return $ WAI.responseLBS
     HT.status502
     [("content-type", "text/plain")]
-    ("Error connecting to gateway:\n\n" ++ TLE.encodeUtf8 (show exc))
+    ("Error connecting to gateway:\n\n" ++ TLE.encodeUtf8 (TL.fromStrict $ show exc))
 
 -- | The different responses that could be generated by a @waiProxyTo@ lookup
 -- function.
@@ -196,7 +199,7 @@
                     , HC.port = port
                     , HC.path = WAI.rawPathInfo req
                     , HC.queryString = WAI.rawQueryString req
-                    , HC.requestHeaders = filter (\(key, _) -> not $ key `member` strippedHeaders) $
+                    , HC.requestHeaders = filter (\(key, _) -> not $ key `Set.member` strippedHeaders) $
                         (case wpsSetIpHeader wps of
                             SIHFromSocket -> (("X-Real-IP", S8.pack $ showSockAddr $ WAI.remoteHost req):)
                             SIHFromHeader ->
@@ -238,13 +241,11 @@
                                 Just conduit -> conduit
                     return $ WAI.ResponseSource
                         (HC.responseStatus res)
-                        (filter (\(key, _) -> not $ key `member` strippedHeaders) $ HC.responseHeaders res) $ do
+                        (filter (\(key, _) -> not $ key `Set.member` strippedHeaders) $ HC.responseHeaders res) $ do
                         yield Flush
                         src =$= conduit
   where
-    strippedHeaders = asSet $ fromList ["content-length", "transfer-encoding", "accept-encoding", "content-encoding"]
-    asSet :: Set a -> Set a
-    asSet = id
+    strippedHeaders = Set.fromList ["content-length", "transfer-encoding", "accept-encoding", "content-encoding"]
 
 -- | Get the HTTP headers for the first request on the stream, returning on
 -- consumed bytes as leftovers. Has built-in limits on how many bytes it will
@@ -263,16 +264,16 @@
         push bs'
             | "\r\n\r\n" `S8.isInfixOf` bs
               || "\n\n" `S8.isInfixOf` bs
-              || length bs > 4096 = leftover bs >> return bs
-            | otherwise = go $ append bs
+              || S8.length bs > 4096 = leftover bs >> return bs
+            | otherwise = go $ mappend bs
           where
             bs = front bs'
-    toHeaders = map toHeader . takeWhile (not . null) . drop 1 . S8.lines
+    toHeaders = map toHeader . takeWhile (not . S8.null) . drop 1 . S8.lines
     toHeader bs =
         (CI.mk key, val)
       where
-        (key, bs') = break (== _colon) bs
-        val = takeWhile (/= _cr) $ dropWhile isSpace $ drop 1 bs'
+        (key, bs') = S.break (== _colon) bs
+        val = S.takeWhile (/= _cr) $ S.dropWhile isSpace $ S.drop 1 bs'
 
 -- | Convert a WAI application into a raw application, using Warp.
 waiToRaw :: WAI.Application -> DCN.Application IO
diff --git a/http-reverse-proxy.cabal b/http-reverse-proxy.cabal
--- a/http-reverse-proxy.cabal
+++ b/http-reverse-proxy.cabal
@@ -1,5 +1,5 @@
 name:                http-reverse-proxy
-version:             0.2.1
+version:             0.2.1.1
 synopsis:            Reverse proxy HTTP requests, either over raw sockets or with WAI
 description:         Provides a simple means of reverse-proxying HTTP requests. The raw approach uses the same technique as leveraged by keter, whereas the WAI approach performs full request/response parsing via WAI and http-conduit.
 homepage:            https://github.com/fpco/http-reverse-proxy
@@ -26,12 +26,13 @@
                      , blaze-builder          >= 0.3
                      , http-conduit           >= 1.6
                      , wai                    >= 1.3
-                     , classy-prelude         >= 0.3
+                     , basic-prelude          >= 0.3.5
                      , network
                      , conduit                >= 0.5
                      , warp                   >= 1.3.4
                      , data-default
                      , wai-logger
+                     , containers
 
 test-suite test
     type: exitcode-stdio-1.0