diff --git a/CHANGES b/CHANGES
--- a/CHANGES
+++ b/CHANGES
@@ -84,3 +84,7 @@
     Note that although the PVP requires a major version bump for added
     instances, it was impossible to write these instances outside of
     the package, so there is no danger of breakage.
+
+Version 0.4.3.1: 8 May 2014
+
+  * Allow transformers-0.4 and mtl-2.2
diff --git a/unbound.cabal b/unbound.cabal
--- a/unbound.cabal
+++ b/unbound.cabal
@@ -1,5 +1,5 @@
 name:           unbound
-version:        0.4.3
+version:        0.4.3.1
 license:        BSD3
 license-file:   LICENSE
 build-type:     Simple
@@ -31,7 +31,8 @@
 Library
   build-depends: base >= 4.3 && < 5,
                  RepLib >= 0.5.3 && < 0.6,
-                 mtl >= 2.0 && < 2.2, transformers >= 0.2.2.0 && < 0.4,
+                 mtl >= 2.0 && < 2.3,
+                 transformers >= 0.2.2.0 && < 0.5,
                  containers >= 0.3 && < 0.6,
                  binary >= 0.7 && < 0.8
   exposed-modules: