diff --git a/hack2-contrib-extra.cabal b/hack2-contrib-extra.cabal
--- a/hack2-contrib-extra.cabal
+++ b/hack2-contrib-extra.cabal
@@ -1,5 +1,5 @@
 Name:                 hack2-contrib-extra
-Version:              2013.6.16
+Version:              2013.6.22
 Build-type:           Simple
 Synopsis:             Hack2 contrib extra
 Description:          Extra middlewares and utilities for Hack2
@@ -28,7 +28,7 @@
                   , bytestring
                   , data-default
                   , time
-                  , air
+                  , air >= 2013.6.22
                   , air-extra
                   , hack2
                   , hack2-contrib
diff --git a/src/Hack2/Contrib/Middleware/UTF8Body.hs b/src/Hack2/Contrib/Middleware/UTF8Body.hs
--- a/src/Hack2/Contrib/Middleware/UTF8Body.hs
+++ b/src/Hack2/Contrib/Middleware/UTF8Body.hs
@@ -7,9 +7,10 @@
 import Hack2
 import qualified Data.ByteString.Char8 as B
 import Hack2.Contrib.Utils (as_string)
+import Data.Maybe (fromMaybe)
 
 utf8_body :: Middleware
 utf8_body app = \env -> do
   r <- app env
   let raw_body = r.body
-  return r {body = raw_body.as_string (unescape_xml > u2b)}
+  return r {body = raw_body.as_string (unescape_xml > fromMaybe def > u2b)}
diff --git a/src/Hack2/Contrib/RequestExtra.hs b/src/Hack2/Contrib/RequestExtra.hs
--- a/src/Hack2/Contrib/RequestExtra.hs
+++ b/src/Hack2/Contrib/RequestExtra.hs
@@ -31,7 +31,7 @@
         .drop 1
         .map (split "=")
         .select (length > is 2)
-        .map tuple2
+        .map (tuple2 > fromMaybe def)
         .map_fst (lower > B.pack)
         .map_snd (B.pack)