diff --git a/GenI.cabal b/GenI.cabal
--- a/GenI.cabal
+++ b/GenI.cabal
@@ -1,5 +1,5 @@
 Name:           GenI
-Version:        0.25.0
+Version:        0.25.0.1
 License:        GPL
 License-file:   LICENSE
 Author:         Carlos Areces and Eric Kow
@@ -57,22 +57,22 @@
   Default:     False
 
 Library
-  Build-depends: base       == 4.9.*
+  Build-depends: base       >= 4.9 && < 4.11
                , binary     == 0.8.*
                , bytestring == 0.10.*
                , containers == 0.5.*
                , deepseq    == 1.4.*
-               , directory  == 1.2.*
+               , directory  >= 1.2 && < 1.4
                , filepath   == 1.4.*
                , hslogger   == 1.2.*
                , json       == 0.9.*
                , mtl        == 2.2.*
                , ordered    == 0.1.*
                , parsec     == 3.1.*
-               , process    == 1.4.*
-               , syb        == 0.6.*
+               , process    >= 1.4 && < 1.7
+               , syb        >= 0.6 && < 0.8
                , text       == 1.2.*
-               , time       == 1.6.*
+               , time       >= 1.6 && < 1.9
                , transformers == 0.5.*
                , yaml-light   == 0.1.*
 
diff --git a/src/NLP/GenI/GeniVal/Internal.hs b/src/NLP/GenI/GeniVal/Internal.hs
--- a/src/NLP/GenI/GeniVal/Internal.hs
+++ b/src/NLP/GenI/GeniVal/Internal.hs
@@ -31,7 +31,7 @@
 import           Data.Binary
 import           Data.Generics       (Data)
 import           Data.List
-import qualified Data.Map            as Map
+import qualified Data.Map.Strict     as Map
 import           Data.Maybe          (fromMaybe, isNothing)
 import           Data.Text           (Text)
 import qualified Data.Text           as T
@@ -372,7 +372,7 @@
   collect l s = foldr collect s l
 
 instance Collectable GeniVal where
-  collect (GeniVal (Just v) cs) s = Map.insertWith' (+) (v,cs) 1 s
+  collect (GeniVal (Just v) cs) s = Map.insertWith (+) (v,cs) 1 s
   collect (GeniVal Nothing _)   s = s
 
 -- | An Idable is something that can be mapped to a unique id.