diff --git a/PowerDNS/API/Servers.hs b/PowerDNS/API/Servers.hs
--- a/PowerDNS/API/Servers.hs
+++ b/PowerDNS/API/Servers.hs
@@ -36,7 +36,8 @@
 import           Control.DeepSeq (NFData)
 import           Data.Aeson (FromJSON(..), ToJSON(..), defaultOptions
                             , Value(String)
-                            , fieldLabelModifier, genericParseJSON
+                            , fieldLabelModifier, constructorTagModifier
+                            , genericParseJSON
                             , allNullaryToStringTag
                             , genericToJSON
                             , (.:), (.=)
@@ -47,7 +48,7 @@
 import           Servant.API
 import           Servant.API.Generic
 
-import           PowerDNS.Internal.Utils (Empty(..), strip)
+import           PowerDNS.Internal.Utils (Empty(..), strip, map1)
 
 ----------------------------------------------------------------------------------------
 
@@ -120,11 +121,11 @@
                 deriving (Eq, Ord, Show, Generic, NFData, Data)
 
 instance ToJSON ObjectType where
-  toJSON = genericToJSON defaultOptions { fieldLabelModifier = fmap toLower . strip "Ty"
+  toJSON = genericToJSON defaultOptions { constructorTagModifier = map1 toLower . strip "Ty"
                                         , allNullaryToStringTag = True }
 
 instance FromJSON ObjectType where
-  parseJSON = genericParseJSON defaultOptions { fieldLabelModifier = fmap toLower . strip "Ty"
+  parseJSON = genericParseJSON defaultOptions { constructorTagModifier = map1 toLower . strip "Ty"
                                               , allNullaryToStringTag = True }
 
 instance FromHttpApiData ObjectType where
diff --git a/PowerDNS/API/TSIGKeys.hs b/PowerDNS/API/TSIGKeys.hs
--- a/PowerDNS/API/TSIGKeys.hs
+++ b/PowerDNS/API/TSIGKeys.hs
@@ -26,9 +26,7 @@
 import           Data.Char (toLower)
 import           Data.Functor ((<&>))
 import           Data.Data (Data)
-#if !(MIN_VERSION_base(4,11,0))
 import           Control.Monad.Fail (MonadFail)
-#endif
 
 import           Control.DeepSeq (NFData)
 import           Data.Aeson ( FromJSON(..), ToJSON(..), Value(String), allNullaryToStringTag
diff --git a/PowerDNS/API/Zones.hs b/PowerDNS/API/Zones.hs
--- a/PowerDNS/API/Zones.hs
+++ b/PowerDNS/API/Zones.hs
@@ -32,7 +32,7 @@
 
 import           Control.DeepSeq (NFData)
 import           Data.Aeson (FromJSON(..), ToJSON(..), allNullaryToStringTag,
-                             defaultOptions, fieldLabelModifier,
+                             defaultOptions, fieldLabelModifier, constructorTagModifier,
                              genericParseJSON, genericToJSON, omitNothingFields)
 import qualified Data.Text as T
 import           Data.Time.Clock.POSIX (POSIXTime)
@@ -125,12 +125,10 @@
   deriving (Eq, Ord, Show, Generic, NFData, Data)
 
 instance ToJSON Kind where
-  toJSON = genericToJSON defaultOptions { fieldLabelModifier = fmap toUpper
-                                        , allNullaryToStringTag = True }
+  toJSON = genericToJSON defaultOptions { allNullaryToStringTag = True }
 
 instance FromJSON Kind where
-  parseJSON = genericParseJSON defaultOptions { fieldLabelModifier = fmap toUpper
-                                              , allNullaryToStringTag = True }
+  parseJSON = genericParseJSON defaultOptions { allNullaryToStringTag = True }
 
 ----------------------------------------------------------------------------------------
 
@@ -233,11 +231,11 @@
                 deriving (Eq, Ord, Show, Generic, NFData, Data)
 
 instance ToJSON ChangeType where
-  toJSON = genericToJSON defaultOptions { fieldLabelModifier = fmap toUpper
+  toJSON = genericToJSON defaultOptions { constructorTagModifier = fmap toUpper
                                         , allNullaryToStringTag = True }
 
 instance FromJSON ChangeType where
-  parseJSON = genericParseJSON defaultOptions { fieldLabelModifier = fmap toUpper
+  parseJSON = genericParseJSON defaultOptions { constructorTagModifier = fmap toUpper
                                               , allNullaryToStringTag = True }
 
 ----------------------------------------------------------------------------------------
diff --git a/PowerDNS/Internal/Utils.hs b/PowerDNS/Internal/Utils.hs
--- a/PowerDNS/Internal/Utils.hs
+++ b/PowerDNS/Internal/Utils.hs
@@ -9,6 +9,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 module PowerDNS.Internal.Utils
   ( strip
+  , map1
   , Empty(..)
   , GEmpty(..)
   )
@@ -23,6 +24,10 @@
                   Just ys -> ys
                   Nothing -> xs
 
+-- | Version of map that applies the function to the first element only
+map1 :: (a -> a) -> [a] -> [a]
+map1 f (x:xs) = f x : xs
+map1 _ xss    = xss
 
 -- | Typeclass of things we can generate empty values of.
 -- This is used to quickly build values from parameters to PowerDNS, because
diff --git a/powerdns.cabal b/powerdns.cabal
--- a/powerdns.cabal
+++ b/powerdns.cabal
@@ -1,6 +1,6 @@
 cabal-version:      >=1.10
 name:               powerdns
-version:            0.2.0
+version:            0.2.1
 license:            BSD3
 license-file:       LICENSE
 copyright:          (c) 2021 Victor Nawothnig
diff --git a/spec/Spec.hs b/spec/Spec.hs
--- a/spec/Spec.hs
+++ b/spec/Spec.hs
@@ -1,15 +1,16 @@
 {-# LANGUAGE OverloadedStrings #-}
-import Data.Either (isRight)
 import Control.Monad (unless)
+import Data.Either (isRight)
 
 import GHC.Stack (HasCallStack)
 
+import Network.HTTP.Client (Manager, defaultManagerSettings, newManager)
+import Servant.Client (ClientEnv, ClientM, mkClientEnv, runClientM)
+import Servant.Client.Core (BaseUrl, ClientError(..), parseBaseUrl,
+                            responseStatusCode)
 import System.IO.Unsafe (unsafePerformIO)
 import Test.Tasty
 import Test.Tasty.HUnit
-import Network.HTTP.Client (newManager, defaultManagerSettings, Manager)
-import Servant.Client (runClientM, mkClientEnv, ClientEnv, ClientM)
-import Servant.Client.Core (parseBaseUrl, BaseUrl, ClientError(..), responseStatusCode)
 
 import PowerDNS.Client
 
@@ -19,7 +20,7 @@
 
 {-# NOINLINE baseUrl #-}
 baseUrl :: BaseUrl
-baseUrl = unsafePerformIO (parseBaseUrl "localhost:8081")
+baseUrl = unsafePerformIO (parseBaseUrl "pdns:8081")
 
 envNoAuth :: ClientEnv
 envNoAuth = mkClientEnv mgr baseUrl
@@ -148,7 +149,7 @@
 
 assertRight :: (Show a, HasCallStack) => String -> Either a b -> IO b
 assertRight preface e = case e of
-  Left e -> assertFailure (msg e)
+  Left e  -> assertFailure (msg e)
   Right r -> pure r
  where msg v = (if null preface then "" else preface ++ "\n") ++
                "Unexpected Left: " ++ show v