diff --git a/Data/CaseInsensitive.hs b/Data/CaseInsensitive.hs
--- a/Data/CaseInsensitive.hs
+++ b/Data/CaseInsensitive.hs
@@ -1,14 +1,19 @@
-{-# LANGUAGE NoImplicitPrelude
+{-# LANGUAGE CPP
+           , NoImplicitPrelude
            , UnicodeSyntax
            , TypeSynonymInstances
            , DeriveDataTypeable
            , FlexibleInstances
   #-}
 
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.CaseInsensitive
--- Copyright   :  (c) 2011 Bas van Dijk
+-- Copyright   :  (c) 2011-2012 Bas van Dijk
 -- License     :  BSD-style (see the file LICENSE)
 -- Maintainer  :  Bas van Dijk <v.dijk.bas@gmail.com>
 --
@@ -125,10 +130,10 @@
 -- <http://hackage.haskell.org/package/text-icu>
 class FoldCase s where foldCase ∷ s → s
 
--- | Note that @foldCase = 'C8.map' 'toLower'@ which is only correct for ASCII encoded strings!
+-- | Note that @foldCase = 'C8.map' 'toLower'@ which is only guaranteed to be correct for ASCII encoded strings!
 instance FoldCase B.ByteString where foldCase = C8.map toLower
 
--- | Note that @foldCase = 'BLC8.map' 'toLower'@ which is only correct for ASCII encoded strings!
+-- | Note that @foldCase = 'BLC8.map' 'toLower'@ which is only guaranteed to be correct for ASCII encoded strings!
 instance FoldCase BL.ByteString where foldCase = BLC8.map toLower
 
 instance FoldCase String  where foldCase = TL.unpack . TL.toCaseFold . TL.pack
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2011 Bas van Dijk
+Copyright (c) 2011-2012 Bas van Dijk
 
 All rights reserved.
 
diff --git a/case-insensitive.cabal b/case-insensitive.cabal
--- a/case-insensitive.cabal
+++ b/case-insensitive.cabal
@@ -1,5 +1,5 @@
 name:          case-insensitive
-version:       0.4.0.1
+version:       0.4.0.2
 cabal-version: >=1.6
 build-type:    Simple
 license:       BSD3
@@ -25,8 +25,8 @@
 
 Library
   GHC-Options: -Wall
-  build-depends: base       >= 3   && < 4.6
-               , bytestring >= 0.9 && < 0.10
+  build-depends: base       >= 3   && < 4.7
+               , bytestring >= 0.9 && < 0.11
                , text       >= 0.3 && < 0.12
                , hashable   >= 1.0 && < 1.2
   exposed-modules: Data.CaseInsensitive