diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.5.1
+-----
+* `transformers` 0.4 compatibility
+
 0.5
 ---
 * Added `(>$)`
diff --git a/contravariant.cabal b/contravariant.cabal
--- a/contravariant.cabal
+++ b/contravariant.cabal
@@ -1,6 +1,6 @@
 name:          contravariant
 category:      Control, Data
-version:       0.5
+version:       0.5.1
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -25,7 +25,7 @@
   build-depends:
     base                            < 5,
     tagged              >= 0.4.4 && < 1,
-    transformers        >= 0.2   && < 0.4,
+    transformers        >= 0.2   && < 0.5,
     transformers-compat >= 0.1   && < 1
 
   if impl(ghc >= 7.4 && < 7.6)