diff --git a/stm-conduit.cabal b/stm-conduit.cabal
--- a/stm-conduit.cabal
+++ b/stm-conduit.cabal
@@ -1,5 +1,5 @@
 Name:                stm-conduit
-Version:             0.4.0
+Version:             0.4.1
 Synopsis:            Introduces conduits to channels, and promotes using
                      conduits concurrently.
 Description:         Provides two simple conduit wrappers around STM
@@ -20,7 +20,7 @@
     
     -- Packages needed in order to build this package.
     Build-depends:     base ==4.*,
-                       transformers ==0.2.*,
+                       transformers >=0.2 && <= 0.4,
                        stm == 2.3.*,
                        stm-chans ==1.3.*,
                        conduit ==0.4.*,