diff --git a/CHANGELOG.yaml b/CHANGELOG.yaml
--- a/CHANGELOG.yaml
+++ b/CHANGELOG.yaml
@@ -2,6 +2,14 @@
 
 releases:
 
+  - version: "0.0.6.0"
+    changes:
+
+      - description: Support for servant-0.12
+        issue: none
+        authors: phadej
+        date: 2018-02-09
+
   - version: "0.0.5.0"
     changes:
 
diff --git a/example/Main.hs b/example/Main.hs
new file mode 100644
--- /dev/null
+++ b/example/Main.hs
@@ -0,0 +1,31 @@
+{-# LANGUAGE OverloadedStrings, DataKinds #-}
+module Main (main) where
+
+import Servant
+import Servant.QuickCheck
+import Test.Hspec
+import Data.Text (Text)
+import System.Environment (getArgs)
+
+main :: IO ()
+main = do
+    args <- getArgs
+    case args of
+        [] -> putStrLn "Not running without arguments. Try --help or --fail-fast."
+        _  -> hspec spec
+
+-- Change to String to reproduce
+-- https://github.com/haskell-servant/servant-quickcheck/issues/41
+type API = Get '[PlainText] Text
+
+api :: Proxy API
+api = Proxy
+
+server :: Server API
+server = return "Sigurð Fáfnirslayer"
+
+spec :: Spec
+spec = describe "example server" $
+    it "mangles UTF-8 in error messages" $
+        withServantServer api (return server) $ \burl ->
+            serverSatisfies api burl defaultArgs (getsHaveCacheControlHeader <%> mempty)
diff --git a/servant-quickcheck.cabal b/servant-quickcheck.cabal
--- a/servant-quickcheck.cabal
+++ b/servant-quickcheck.cabal
@@ -1,5 +1,5 @@
 name:                servant-quickcheck
-version:             0.0.5.0
+version:             0.0.6.0
 synopsis:            QuickCheck entire APIs
 description:
  This packages provides QuickCheck properties that are tested across an entire
@@ -17,7 +17,7 @@
 tested-with:
   GHC==7.10.3,
   GHC==8.0.2,
-  GHC==8.2.1
+  GHC==8.2.2
 
 source-repository head
   type: git
@@ -45,14 +45,14 @@
                      , hspec >= 2.2 && < 2.5
                      , http-client >= 0.4.30 && < 0.6
                      , http-media >= 0.6 && <0.8
-                     , http-types > 0.8 && < 0.11
+                     , http-types > 0.8 && < 0.13
                      , mtl > 2.1 && < 2.3
                      , pretty == 1.1.*
                      , process >= 1.2 && < 1.7
-                     , QuickCheck > 2.7 && < 2.11
-                     , servant > 0.6 && < 0.13
-                     , servant-client > 0.6 && < 0.13
-                     , servant-server > 0.6 && < 0.13
+                     , QuickCheck > 2.7 && < 2.12
+                     , servant >= 0.13 && < 0.14
+                     , servant-client >= 0.13 && < 0.14
+                     , servant-server >= 0.13 && < 0.14
                      , split == 0.2.*
                      , string-conversions > 0.3 && < 0.5
                      , temporary == 1.2.*
@@ -114,3 +114,17 @@
                      , ScopedTypeVariables
   if flag(long-tests)
       cpp-options: -DLONG_TESTS
+
+test-suite example
+  type: exitcode-stdio-1.0
+  main-is: Main.hs
+  hs-source-dirs:
+    example
+  ghc-options: -Wall
+  build-depends:
+      base
+    , hspec
+    , servant-server
+    , servant-quickcheck
+    , text
+  default-language: Haskell2010
diff --git a/src/Servant/QuickCheck/Internal/HasGenRequest.hs b/src/Servant/QuickCheck/Internal/HasGenRequest.hs
--- a/src/Servant/QuickCheck/Internal/HasGenRequest.hs
+++ b/src/Servant/QuickCheck/Internal/HasGenRequest.hs
@@ -78,7 +78,7 @@
 #endif
 
 instance (Arbitrary c, HasGenRequest b, ToHttpApiData c )
-    => HasGenRequest (Capture x c :> b) where
+    => HasGenRequest (Capture' mods x c :> b) where
     genRequest _ = (oldf, do
       old' <- old
       new' <- toUrlPiece <$> new
@@ -101,10 +101,10 @@
 #endif
 
 instance (Arbitrary c, KnownSymbol h, HasGenRequest b, ToHttpApiData c)
-    => HasGenRequest (Header h c :> b) where
+    => HasGenRequest (Header' mods h c :> b) where
     genRequest _ = (oldf, do
       old' <- old
-      new' <- toUrlPiece <$> new
+      new' <- toUrlPiece <$> new  -- TODO: generate lenient or/and optional
       return $ \burl -> let r = old' burl in r {
           requestHeaders = (hdr, cs new') : requestHeaders r })
       where
@@ -113,9 +113,9 @@
         new = arbitrary :: Gen c
 
 instance (AllMimeRender x c, Arbitrary c, HasGenRequest b)
-    => HasGenRequest (ReqBody x c :> b) where
+    => HasGenRequest (ReqBody' mods x c :> b) where
     genRequest _ = (oldf, do
-      old' <- old
+      old' <- old  -- TODO: generate lenient
       new' <- new
       (ct, bd) <- elements $ allMimeRender (Proxy :: Proxy x) new'
       return $ \burl -> let r = old' burl in r {
@@ -127,9 +127,9 @@
         new = arbitrary :: Gen c
 
 instance (KnownSymbol x, Arbitrary c, ToHttpApiData c, HasGenRequest b)
-    => HasGenRequest (QueryParam x c :> b) where
+    => HasGenRequest (QueryParam' mods x c :> b) where
     genRequest _ = (oldf, do
-      new' <- new
+      new' <- new  -- TODO: generate lenient or/and optional
       old' <- old
       return $ \burl -> let r = old' burl
                             newExpr = param <> "=" <> cs (toQueryParam new')