diff --git a/CHANGES b/CHANGES
--- a/CHANGES
+++ b/CHANGES
@@ -57,3 +57,8 @@
 Version 0.4.0.2: 10 April 2012
 
   * Bump 'mtl' upper bound to allow mtl-2.1
+
+Version 0.4.1: 5 June 2012
+
+  * Patch from Vilhelm Sjöberg changing acompareR1 to return EQ for
+    Abstract1
diff --git a/Unbound/LocallyNameless/Alpha.hs b/Unbound/LocallyNameless/Alpha.hs
--- a/Unbound/LocallyNameless/Alpha.hs
+++ b/Unbound/LocallyNameless/Alpha.hs
@@ -514,7 +514,8 @@
                         (Nothing, Nothing) -> loop rest
                  loop [] = error "acompareR1 found no constructors! Please report this as a bug."
              in loop cons
-acompareR1 r1 _ = error ("compareR1 not supported for " ++ show r1)
+acompareR1 (Abstract1 _) _ = \_ _ -> EQ           
+acompareR1 r1 _ = error ("acompareR1 not supported for " ++ show r1)
 
 compareTupM :: MTup AlphaD l -> AlphaCtx -> l -> l -> Ordering
 compareTupM MNil _ Nil Nil = EQ
diff --git a/unbound.cabal b/unbound.cabal
--- a/unbound.cabal
+++ b/unbound.cabal
@@ -1,5 +1,5 @@
 name:           unbound
-version:        0.4.0.2
+version:        0.4.1
 license:        BSD3
 license-file:   LICENSE
 build-type:     Simple
@@ -30,7 +30,7 @@
 
 Library
   build-depends: base >= 4.3 && < 5,
-                 RepLib >= 0.5.1 && < 0.6,
+                 RepLib >= 0.5.3 && < 0.6,
                  mtl >= 2.0 && < 2.2, transformers >= 0.2.2.0 && < 0.4,
                  containers >= 0.3 && < 0.5
   exposed-modules: