diff --git a/ChristmasTree.cabal b/ChristmasTree.cabal
--- a/ChristmasTree.cabal
+++ b/ChristmasTree.cabal
@@ -1,7 +1,7 @@
 cabal-version:      >=1.2.3
 build-type:         Simple
 name:               ChristmasTree
-version:            0.2
+version:            0.2.1
 license:            LGPL
 license-file:       COPYRIGHT
 maintainer:         Marcos Viera <mviera@fing.edu.uy>
@@ -12,7 +12,7 @@
 stability:          Experimental
 copyright:          Universiteit Utrecht
 build-depends:      base >= 4 && < 5, haskell98, template-haskell >= 2.4, containers,
-                    fgl>=5.4, TTTAS >= 0.4 , uulib >= 0.9.11 
+                    fgl == 5.4.2.2, TTTAS >= 0.4 , uulib >= 0.9.11 
 exposed-modules:    Text.GRead, Text.GShow, 
                     Text.GRead.Derive, Text.GRead.Grammar,
                     Text.GRead.Derive.BindingGroup,