diff --git a/named-servant-client.cabal b/named-servant-client.cabal
--- a/named-servant-client.cabal
+++ b/named-servant-client.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.12
 name: named-servant-client
-version: 0.1.1
+version: 0.2.0
 synopsis: client support for named-servant
 maintainer: kristof@resonata.be
 copyright: Kristof Bastiaensen 2020
@@ -24,5 +24,5 @@
         base >= 4.7 && < 5,
         servant >= 0.17 && < 0.18,
         servant-client-core >= 0.17 && < 0.18,
-        named-servant == 0.1.1,
+        named-servant == 0.2.0,
         named >= 0.3 && < 0.5
diff --git a/src/Servant/Client/Named.hs b/src/Servant/Client/Named.hs
--- a/src/Servant/Client/Named.hs
+++ b/src/Servant/Client/Named.hs
@@ -67,11 +67,11 @@
       => HasClient m (NamedQueryFlag sym :> api) where
 
   type Client m (NamedQueryFlag sym :> api) =
-    sym :! Bool -> Client m api
+    sym :? Bool -> Client m api
 
-  clientWithRoute pm Proxy req (Arg paramlist) =
-    clientWithRoute pm (Proxy :: Proxy (QueryFlag sym :> api)) req
-                    paramlist
+  clientWithRoute pm Proxy req (ArgF paramlist) =
+    clientWithRoute pm (Proxy :: Proxy (QueryFlag sym :> api)) req $
+                    fromMaybe False paramlist
                     
   hoistClientMonad pm _ f cl as =
     hoistClientMonad pm (Proxy :: Proxy api) f (cl as)