diff --git a/hack2-contrib.cabal b/hack2-contrib.cabal
--- a/hack2-contrib.cabal
+++ b/hack2-contrib.cabal
@@ -1,5 +1,5 @@
 Name:                 hack2-contrib
-Version:              2013.6.16
+Version:              2013.6.22
 Build-type:           Simple
 Synopsis:             Hack2 contrib
 Description:          Common middlewares and utilities for Hack2
@@ -27,7 +27,7 @@
                   , bytestring
                   , data-default
                   , time
-                  , air
+                  , air >= 2013.6.22
                   , hack2
                   , utf8-string
                   
diff --git a/src/Hack2/Contrib/Middleware/UserMime.hs b/src/Hack2/Contrib/Middleware/UserMime.hs
--- a/src/Hack2/Contrib/Middleware/UserMime.hs
+++ b/src/Hack2/Contrib/Middleware/UserMime.hs
@@ -14,7 +14,7 @@
 user_mime :: [(ByteString, ByteString)] -> Middleware
 user_mime h app env = do
   r <- app env
-  case h.only_fst.find mime >>= flip lookup h of
+  case h.map fst.find mime >>= flip lookup h of
     Nothing -> return r
     Just v -> return - r.set_content_type v
   where mime x = env.path_info.B.unpack.ends_with ('.' : x.B.unpack)