diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,10 @@
 # ChangeLog for http-semantics
 
+## 0.3.1
+
+* Adding defaultAux and auxSendPing for client.
+* Adding defaultAux for server.
+
 ## 0.3.0
 
 * Breaking change: fillFileBodyGetNext takes Sentinel instead of
diff --git a/Network/HTTP/Semantics/Client.hs b/Network/HTTP/Semantics/Client.hs
--- a/Network/HTTP/Semantics/Client.hs
+++ b/Network/HTTP/Semantics/Client.hs
@@ -39,7 +39,9 @@
 
     -- * Aux
     Aux,
+    defaultAux,
     auxPossibleClientStreams,
+    auxSendPing,
 
     -- * Types
     Scheme,
diff --git a/Network/HTTP/Semantics/Client/Internal.hs b/Network/HTTP/Semantics/Client/Internal.hs
--- a/Network/HTTP/Semantics/Client/Internal.hs
+++ b/Network/HTTP/Semantics/Client/Internal.hs
@@ -2,6 +2,7 @@
     Request (..),
     Response (..),
     Aux (..),
+    defaultAux,
 ) where
 
 import Network.HTTP.Semantics.Types (InpObj (..), OutObj (..))
@@ -16,4 +17,13 @@
 data Aux = Aux
     { auxPossibleClientStreams :: IO Int
     -- ^ How many streams can be created without blocking.
+    , auxSendPing :: IO ()
+    -- ^ Sending a ping.
     }
+
+defaultAux :: Aux
+defaultAux =
+    Aux
+        { auxPossibleClientStreams = return 0
+        , auxSendPing = return ()
+        }
diff --git a/Network/HTTP/Semantics/FillBuf.hs b/Network/HTTP/Semantics/FillBuf.hs
--- a/Network/HTTP/Semantics/FillBuf.hs
+++ b/Network/HTTP/Semantics/FillBuf.hs
@@ -1,6 +1,3 @@
-{-# LANGUAGE NamedFieldPuns #-}
-{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
 module Network.HTTP.Semantics.FillBuf (
@@ -25,7 +22,7 @@
 import Data.Int (Int64)
 import Data.Maybe
 import Foreign.Ptr (plusPtr)
-import Network.ByteOrder
+import Network.ByteOrder hiding (start)
 import Network.HTTP.Semantics.Client
 
 ----------------------------------------------------------------
diff --git a/Network/HTTP/Semantics/Server.hs b/Network/HTTP/Semantics/Server.hs
--- a/Network/HTTP/Semantics/Server.hs
+++ b/Network/HTTP/Semantics/Server.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
-
 module Network.HTTP.Semantics.Server (
     -- * HTTP server
     Server,
@@ -20,6 +18,7 @@
 
     -- * Aux
     Aux,
+    defaultAux,
     auxTimeHandle,
     auxMySockAddr,
     auxPeerSockAddr,
@@ -66,12 +65,24 @@
 import qualified Data.ByteString.UTF8 as UTF8
 import Data.IORef
 import qualified Network.HTTP.Types as H
+import Network.Socket
+import qualified System.TimeManager as T
 
 import Network.HTTP.Semantics
 import Network.HTTP.Semantics.File
 import Network.HTTP.Semantics.ReadN
 import Network.HTTP.Semantics.Server.Internal
 import Network.HTTP.Semantics.Status
+
+----------------------------------------------------------------
+
+defaultAux :: Aux
+defaultAux =
+    Aux
+        { auxTimeHandle = T.emptyHandle
+        , auxMySockAddr = SockAddrInet 0 0
+        , auxPeerSockAddr = SockAddrInet 0 0
+        }
 
 ----------------------------------------------------------------
 
diff --git a/Network/HTTP/Semantics/Types.hs b/Network/HTTP/Semantics/Types.hs
--- a/Network/HTTP/Semantics/Types.hs
+++ b/Network/HTTP/Semantics/Types.hs
@@ -61,7 +61,7 @@
     | OutBodyFile FileSpec
 
 data OutBodyIface = OutBodyIface
-    { outBodyUnmask :: (forall x. IO x -> IO x)
+    { outBodyUnmask :: forall x. IO x -> IO x
     -- ^ Unmask exceptions in the thread spawned for the request body
     --
     -- This is used in the client: we spawn the new thread for the request body
diff --git a/http-semantics.cabal b/http-semantics.cabal
--- a/http-semantics.cabal
+++ b/http-semantics.cabal
@@ -1,12 +1,12 @@
 cabal-version:   3.0
 name:            http-semantics
-version:         0.3.0
+version:         0.3.1
 license:         BSD-3-Clause
 license-file:    LICENSE
 maintainer:      Kazu Yamamoto <kazu@iij.ad.jp>
 author:          Kazu Yamamoto <kazu@iij.ad.jp>
 homepage:        https://github.com/kazu-yamamoto/http-semantics
-synopsis:        HTTP senmatics libarry
+synopsis:        HTTP semantics library
 description:     Version-independent common parts of HTTP
 category:        Network
 build-type:      Simple
@@ -46,5 +46,5 @@
         http-types >=0.12 && <0.13,
         network,
         network-byte-order,
-        time-manager,
+        time-manager >= 0.2.4,
         utf8-string