diff --git a/Network/HTTP2/Client.hs b/Network/HTTP2/Client.hs
--- a/Network/HTTP2/Client.hs
+++ b/Network/HTTP2/Client.hs
@@ -71,7 +71,17 @@
     rstRateLimit,
 
     -- * Common configuration
-    Config (..),
+    Config,
+    defaultConfig,
+    confWriteBuffer,
+    confBufferSize,
+    confSendAll,
+    confReadN,
+    confPositionReadMaker,
+    confTimeoutManager,
+    confMySockAddr,
+    confPeerSockAddr,
+    confReadNTimeout,
     allocSimpleConfig,
     allocSimpleConfig',
     freeSimpleConfig,
diff --git a/Network/HTTP2/Client/Internal.hs b/Network/HTTP2/Client/Internal.hs
--- a/Network/HTTP2/Client/Internal.hs
+++ b/Network/HTTP2/Client/Internal.hs
@@ -1,6 +1,7 @@
 module Network.HTTP2.Client.Internal (
     Request (..),
     Response (..),
+    Config (..),
     ClientConfig (..),
     Settings (..),
     Aux (..),
diff --git a/Network/HTTP2/H2/Types.hs b/Network/HTTP2/H2/Types.hs
--- a/Network/HTTP2/H2/Types.hs
+++ b/Network/HTTP2/H2/Types.hs
@@ -14,6 +14,7 @@
  )
 import qualified Control.Exception as E
 import Data.IORef
+import Foreign.Ptr (nullPtr)
 import Network.Control
 import Network.HTTP.Semantics.Client
 import Network.HTTP.Semantics.IO
@@ -271,6 +272,22 @@
     -- ^ This is copied into 'Aux', if exist, on server.
     , confReadNTimeout :: Bool
     }
+
+-- | Default config. This is just a template to modify via
+--   field names. Don't use this without modifications.
+defaultConfig :: Config
+defaultConfig =
+    Config
+        { confWriteBuffer = nullPtr
+        , confBufferSize = 0
+        , confSendAll = \_ -> return ()
+        , confReadN = \_ -> return ""
+        , confPositionReadMaker = defaultPositionReadMaker
+        , confTimeoutManager = T.defaultManager
+        , confMySockAddr = SockAddrInet 0 0
+        , confPeerSockAddr = SockAddrInet 0 0
+        , confReadNTimeout = False
+        }
 
 isAsyncException :: Exception e => e -> Bool
 isAsyncException e =
diff --git a/Network/HTTP2/Server.hs b/Network/HTTP2/Server.hs
--- a/Network/HTTP2/Server.hs
+++ b/Network/HTTP2/Server.hs
@@ -51,7 +51,17 @@
     rstRateLimit,
 
     -- * Common configuration
-    Config (..),
+    Config,
+    defaultConfig,
+    confWriteBuffer,
+    confBufferSize,
+    confSendAll,
+    confReadN,
+    confPositionReadMaker,
+    confTimeoutManager,
+    confMySockAddr,
+    confPeerSockAddr,
+    confReadNTimeout,
     allocSimpleConfig,
     allocSimpleConfig',
     freeSimpleConfig,
diff --git a/Network/HTTP2/Server/Internal.hs b/Network/HTTP2/Server/Internal.hs
--- a/Network/HTTP2/Server/Internal.hs
+++ b/Network/HTTP2/Server/Internal.hs
@@ -1,6 +1,8 @@
 module Network.HTTP2.Server.Internal (
     Request (..),
     Response (..),
+    Config (..),
+    ServerConfig (..),
     Aux (..),
 
     -- * Low level
diff --git a/http2.cabal b/http2.cabal
--- a/http2.cabal
+++ b/http2.cabal
@@ -1,6 +1,6 @@
 cabal-version:      >=1.10
 name:               http2
-version:            5.3.11
+version:            5.4.0
 license:            BSD3
 license-file:       LICENSE
 maintainer:         Kazu Yamamoto <kazu@iij.ad.jp>
@@ -114,14 +114,14 @@
         bytestring >=0.10,
         case-insensitive >=1.2 && <1.3,
         containers >=0.6,
-        http-semantics >= 0.3.1 && <0.4,
+        http-semantics >= 0.4 && <0.5,
         http-types >=0.12 && <0.13,
         iproute >= 1.7 && < 1.8,
         network >=3.1,
         network-byte-order >=0.1.7 && <0.2,
         network-control >=0.1 && <0.2,
         stm >=2.5 && <2.6,
-        time-manager >=0.2 && <0.4,
+        time-manager >=0.2.3 && <0.4,
         unix-time >=0.4.11 && <0.5,
         utf8-string >=1.0 && <1.1