diff --git a/src/Web/Users/Postgresql.hs b/src/Web/Users/Postgresql.hs
--- a/src/Web/Users/Postgresql.hs
+++ b/src/Web/Users/Postgresql.hs
@@ -2,12 +2,17 @@
 {-# LANGUAGE QuasiQuotes #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE CPP #-}
 module Web.Users.Postgresql () where
 
 import Web.Users.Types
 
 import Control.Monad
+#if MIN_VERSION_mtl(2,2,0)
 import Control.Monad.Except
+#else
+import Control.Monad.Error
+#endif
 import Data.Aeson
 import Data.Int
 import Data.Maybe
@@ -65,6 +70,17 @@
     do r <- check
        unless r a
 
+#if MIN_VERSION_mtl(2,2,0)
+type ErrorT = ExceptT
+runErrorT :: ErrorT e m a -> m (Either e a)
+runErrorT = runExceptT
+#else
+-- a hack... :-(
+instance Error UpdateUserError where
+    noMsg = error "Calling fail not supported"
+    strMsg = error "Calling fail not supported"
+#endif
+
 instance UserStorageBackend Connection where
     type UserId Connection = Int64
     initUserBackend conn =
@@ -138,7 +154,7 @@
              Nothing ->
                  return $ Left UserDoesntExit
              Just origUser ->
-                 runExceptT $
+                 runErrorT $
                  do let newUser = updateFun origUser
                     when (u_name newUser /= u_name origUser) $
                          do [(Only counter)] <-
diff --git a/users-postgresql-simple.cabal b/users-postgresql-simple.cabal
--- a/users-postgresql-simple.cabal
+++ b/users-postgresql-simple.cabal
@@ -1,5 +1,5 @@
 name:                users-postgresql-simple
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            A PostgreSQL backend for the users package
 description:         This library is a backend driver using <http://hackage.haskell.org/package/postgresql-simple postgresql-simple> for
                      <http://hackage.haskell.org/package/users the "users" library>.
@@ -37,7 +37,7 @@
                        postgresql-simple >=0.4,
                        aeson >=0.8,
                        text >=1.2,
-                       mtl >=2.2,
+                       mtl >=2.1,
                        uuid >=1.3,
                        bytestring >=0.10,
                        time >=1.4