diff --git a/servant.cabal b/servant.cabal
--- a/servant.cabal
+++ b/servant.cabal
@@ -1,5 +1,5 @@
 name:                servant
-version:             0.4.1
+version:             0.4.2
 synopsis:            A family of combinators for defining webservices APIs
 description:
   A family of combinators for defining webservices APIs and serving them
@@ -55,7 +55,7 @@
     , http-media >= 0.4 && < 0.7
     , http-types == 0.8.*
     , text >= 1 && < 2
-    , string-conversions >= 0.3 && < 0.4
+    , string-conversions >= 0.3 && < 0.5
     , network-uri >= 2.6
   hs-source-dirs: src
   default-language: Haskell2010
diff --git a/src/Servant/API/Capture.hs b/src/Servant/API/Capture.hs
--- a/src/Servant/API/Capture.hs
+++ b/src/Servant/API/Capture.hs
@@ -9,6 +9,7 @@
 -- | Capture a value from the request path under a certain type @a@.
 --
 -- Example:
+--
 -- >>>            -- GET /books/:isbn
 -- >>> type MyApi = "books" :> Capture "isbn" Text :> Get '[JSON] Book
 data Capture (sym :: Symbol) a
diff --git a/src/Servant/API/ContentTypes.hs b/src/Servant/API/ContentTypes.hs
--- a/src/Servant/API/ContentTypes.hs
+++ b/src/Servant/API/ContentTypes.hs
@@ -166,7 +166,7 @@
     handleAcceptH _ (AcceptHeader accept) val = M.mapAcceptMedia lkup accept
       where pctyps = Proxy :: Proxy ctyps
             amrs = allMimeRender pctyps val
-            lkup = fmap (\(a,b) -> (a, (cs $ show a, b))) amrs
+            lkup = fmap (\(a,b) -> (a, (fromStrict $ M.renderHeader a, b))) amrs
 
 
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