diff --git a/mighttpd2.cabal b/mighttpd2.cabal
--- a/mighttpd2.cabal
+++ b/mighttpd2.cabal
@@ -1,5 +1,5 @@
 Name:                   mighttpd2
-Version:                3.3.2
+Version:                3.3.3
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -71,7 +71,7 @@
                       , bytestring
                       , directory
                       , filepath
-                      , http-client
+                      , http-client >= 0.5
                       , http-date
                       , http-types
                       , mighttpd2
@@ -123,7 +123,7 @@
   Build-Depends:        base >= 4 && < 5
                       , hspec >= 1.3
                       , mighttpd2
-                      , http-client
+                      , http-client >= 0.5
   if flag(tls)
     Build-Depends:      tls
                       , warp-tls >= 3.2 && < 3.3
diff --git a/src/Server.hs b/src/Server.hs
--- a/src/Server.hs
+++ b/src/Server.hs
@@ -242,4 +242,4 @@
   where
     responseTimeout
       | opt_proxy_timeout opt == 0 = H.managerResponseTimeout H.defaultManagerSettings
-      | otherwise                  = Just (opt_proxy_timeout opt * 1000000) -- micro seconds
+      | otherwise                  = H.responseTimeoutMicro (opt_proxy_timeout opt * 1000000) -- micro seconds