diff --git a/bff-mono.cabal b/bff-mono.cabal
--- a/bff-mono.cabal
+++ b/bff-mono.cabal
@@ -1,5 +1,5 @@
 name:                bff-mono
-version:             0.2.0
+version:             0.2.1
 synopsis:            "Bidirectionalization for Free" for Monomorphic Transformations
 description:         This package provides a way to make a bidirectional 
                      transformation (a getter/setter pair, or so-called lens) 
@@ -15,7 +15,7 @@
 author:              Kazutaka Matsuda, 
                      Meng Wang
 maintainer:          kztk@is.s.u-tokyo.ac.jp
-category:            Language
+category:            Data, Lenses
 build-type:          Simple
 cabal-version:       >=1.8