diff --git a/Yesod/Internal/Core.hs b/Yesod/Internal/Core.hs
--- a/Yesod/Internal/Core.hs
+++ b/Yesod/Internal/Core.hs
@@ -909,6 +909,9 @@
           , W.queryString    = []
           , W.requestBody    = mempty
           , W.vault          = mempty
+#if MIN_VERSION_wai(1, 4, 0)
+          , W.requestBodyLength = W.KnownLength 0
+#endif
           }
       fakeRequest =
         Request
diff --git a/yesod-core.cabal b/yesod-core.cabal
--- a/yesod-core.cabal
+++ b/yesod-core.cabal
@@ -1,5 +1,5 @@
 name:            yesod-core
-version:         1.1.8.1
+version:         1.1.8.2
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>
@@ -50,7 +50,7 @@
     build-depends:   base                  >= 4.3      && < 5
                    , time                  >= 1.1.4
                    , yesod-routes          >= 1.1      && < 1.2
-                   , wai                   >= 1.3      && < 1.4
+                   , wai                   >= 1.3      && < 1.5
                    , wai-extra             >= 1.3      && < 1.4
                    , bytestring            >= 0.9.1.4
                    , text                  >= 0.7      && < 0.12
@@ -83,8 +83,8 @@
                    , conduit               >= 0.5
                    , resourcet             >= 0.3      && < 0.5
                    , lifted-base           >= 0.1
-                   , blaze-html            >= 0.5      && < 0.6
-                   , blaze-markup          >= 0.5.1    && < 0.6
+                   , blaze-html            >= 0.5
+                   , blaze-markup          >= 0.5.1
 
     exposed-modules: Yesod.Content
                      Yesod.Core
