diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 3.1.6
+
+* Adding back http-types 0.8 support [#449](https://github.com/yesodweb/wai/pull/449)
+
 ## 3.1.5
 
 * Using	http-types v0.9.
diff --git a/Network/Wai/Handler/Warp/Conduit.hs b/Network/Wai/Handler/Warp/Conduit.hs
--- a/Network/Wai/Handler/Warp/Conduit.hs
+++ b/Network/Wai/Handler/Warp/Conduit.hs
@@ -64,11 +64,6 @@
                     assert (count' == 0) $ I.writeIORef ref count'
                     return x
 
--- | Extract the underlying @Source@ from an @IsolatedBSSource@, which will not
--- perform any more isolation.
-isourceDone :: ISource -> Source
-isourceDone (ISource src _) = src
-
 ----------------------------------------------------------------
 
 data CSource = CSource !Source !(I.IORef ChunkState)
diff --git a/Network/Wai/Handler/Warp/Response.hs b/Network/Wai/Handler/Warp/Response.hs
--- a/Network/Wai/Handler/Warp/Response.hs
+++ b/Network/Wai/Handler/Warp/Response.hs
@@ -9,7 +9,6 @@
   , sanitizeHeaderValue -- for testing
   , fileRange -- for testing
   , warpVersion
-  , defaultServerValue
   , addDate
   , addServer
   , hasBody
@@ -19,6 +18,10 @@
 #define MIN_VERSION_base(x,y,z) 1
 #endif
 
+#ifndef MIN_VERSION_http_types
+#define MIN_VERSION_http_types(x,y,z) 1
+#endif
+
 import Blaze.ByteString.Builder.HTTP (chunkedTransferEncoding, chunkedTransferTerminator)
 #if __GLASGOW_HASKELL__ < 709
 import Control.Applicative
@@ -31,7 +34,6 @@
 import qualified Data.ByteString.Char8 as S8
 import Data.ByteString.Builder (byteString, Builder)
 import Data.ByteString.Builder.Extra (flush)
-import qualified Data.ByteString.Char8 as B (pack)
 import qualified Data.CaseInsensitive as CI
 import Data.Function (on)
 import Data.List (deleteBy)
@@ -48,7 +50,9 @@
 import Data.Version (showVersion)
 import Data.Word8 (_cr, _lf)
 import qualified Network.HTTP.Types as H
+#if MIN_VERSION_http_types(0,9,0)
 import qualified Network.HTTP.Types.Header as H
+#endif
 import Network.Wai
 import Network.Wai.Handler.Warp.Buffer (toBuilderBuffer)
 import qualified Network.Wai.Handler.Warp.Date as D
@@ -380,7 +384,11 @@
 ----------------------------------------------------------------
 
 addTransferEncoding :: H.ResponseHeaders -> H.ResponseHeaders
+#if MIN_VERSION_http_types(0,9,0)
 addTransferEncoding hdrs = (H.hTransferEncoding, "chunked") : hdrs
+#else
+addTransferEncoding hdrs = ("transfer-encoding", "chunked") : hdrs
+#endif
 
 addDate :: D.DateCache -> IndexedHeader -> H.ResponseHeaders -> IO H.ResponseHeaders
 addDate dc rspidxhdr hdrs = case rspidxhdr ! idxDate of
@@ -395,12 +403,9 @@
 warpVersion :: String
 warpVersion = showVersion Paths_warp.version
 
-defaultServerValue :: HeaderValue
-defaultServerValue = B.pack $ "Warp/" ++ warpVersion
-
 addServer :: HeaderValue -> IndexedHeader -> H.ResponseHeaders -> H.ResponseHeaders
-addServer defaultServerValue' rspidxhdr hdrs = case rspidxhdr ! idxServer of
-    Nothing -> (H.hServer, defaultServerValue') : hdrs
+addServer serverName rspidxhdr hdrs = case rspidxhdr ! idxServer of
+    Nothing -> (H.hServer, serverName) : hdrs
     _       -> hdrs
 
 ----------------------------------------------------------------
diff --git a/Network/Wai/Handler/Warp/Run.hs b/Network/Wai/Handler/Warp/Run.hs
--- a/Network/Wai/Handler/Warp/Run.hs
+++ b/Network/Wai/Handler/Warp/Run.hs
@@ -370,11 +370,6 @@
                     -> Settings
                     -> IO ()
 
--- Serve an HTTP\/2-aware application, rejecting clients that attempt to use an
--- older protocol version.
-serveHTTP2Only :: HTTP2Application -> ServeConnection
-serveHTTP2Only = error "serveHTTP2Only not implemented"
-
 -- Serve an HTTP\/2-unaware Application to a connection over any HTTP version.
 serveDefault :: Application -> ServeConnection
 serveDefault app = serveHTTP2 (promoteApplication app) app
diff --git a/warp.cabal b/warp.cabal
--- a/warp.cabal
+++ b/warp.cabal
@@ -1,5 +1,5 @@
 Name:                warp
-Version:             3.1.5
+Version:             3.1.6
 Synopsis:            A fast, light-weight web server for WAI applications.
 License:             MIT
 License-file:        LICENSE
@@ -40,7 +40,7 @@
                    , case-insensitive          >= 0.2
                    , containers
                    , ghc-prim
-                   , http-types                >= 0.9
+                   , http-types                >= 0.8.5
                    , iproute                   >= 1.3.1
                    , http2                     >= 1.1
                    , simple-sendfile           >= 0.2.7    && < 0.3
@@ -139,7 +139,7 @@
                    , case-insensitive          >= 0.2
                    , ghc-prim
                    , HTTP
-                   , http-types                >= 0.9
+                   , http-types                >= 0.8.5
                    , iproute                   >= 1.3.1
                    , lifted-base               >= 0.1
                    , simple-sendfile           >= 0.2.4    && < 0.3