diff --git a/Control/Monatron/IdT.hs b/Control/Monatron/IdT.hs
--- a/Control/Monatron/IdT.hs
+++ b/Control/Monatron/IdT.hs
@@ -9,5 +9,5 @@
     tbind m f    = IdT $ runIdT m >>= runIdT . f 
     
 instance FMonadT IdT where
-    tmap' d1 d2 g f       = IdT . f . fmapD d1 g . runIdT
+    tmap' d1 _d2 g f       = IdT . f . fmapD d1 g . runIdT
 
diff --git a/Control/Monatron/Open.hs b/Control/Monatron/Open.hs
--- a/Control/Monatron/Open.hs
+++ b/Control/Monatron/Open.hs
@@ -2,7 +2,7 @@
 
 module Control.Monatron.Open where
 
-import Control.Monatron.Monatron
+import Control.Monatron.Monatron ()
 import Control.Monatron.AutoLift
 
 infixr 9 :+:
diff --git a/Monatron.cabal b/Monatron.cabal
--- a/Monatron.cabal
+++ b/Monatron.cabal
@@ -1,5 +1,5 @@
 name:         Monatron
-version:      0.3
+version:      0.3.1
 license:      BSD3
 license-file: LICENSE
 author:       Mauro Jaskelioff
@@ -29,6 +29,6 @@
 	Control.Monatron.Zipper
 	Control.Monatron.Open
 	Control.Monatron.ZipperExamples
-build-depends: base >= 2 && < 3
+build-depends: base >= 2 && < 5
 extensions: 
 	Rank2Types