diff --git a/abt.cabal b/abt.cabal
--- a/abt.cabal
+++ b/abt.cabal
@@ -1,5 +1,5 @@
 name:                abt
-version:             0.1.0.2
+version:             0.1.0.2.1
 synopsis:            Abstract binding trees for Haskell
 description:         A Haskell port of the Carnegie Mellon ABT library (SML), with some improvements.
 license:             MIT
@@ -24,7 +24,8 @@
   build-depends:       base >=4.7 && <4.8,
                        vinyl >=0.5,
                        profunctors >=4.3.2,
-                       transformers
+                       transformers >=0.2,
+                       transformers-compat >=0.3
   ghc-options:         -Wall
   hs-source-dirs:      src
   default-language:    Haskell2010