diff --git a/Data/DString.hs b/Data/DString.hs
--- a/Data/DString.hs
+++ b/Data/DString.hs
@@ -8,11 +8,12 @@
 -- Maintainer  :  Bas van Dijk <v.dijk.bas@gmail.com>
 -- Stability   :  experimental
 --
--- Difference strings: a data structure for O(1) append on
--- strings. Note that a DString is just a newtype wrapper around a
--- 'DList Char'.  The reason we need a new type instead of just a type
--- synonym is that we can have an 'instance IsString DString' so we
--- can write overloaded string literals of type DString.
+-- Difference strings: a data structure for O(1) append on strings. Note that a
+-- DString is just a newtype wrapper around a 'DList Char'. The reason we need a
+-- new type instead of just a type synonym is that we can have an 'instance
+-- IsString DString' without using language extensions (TypeSynonymInstances or
+-- FlexibleInstances) so we can write overloaded string literals of type
+-- DString.
 --
 -----------------------------------------------------------------------------
 
diff --git a/dstring.cabal b/dstring.cabal
--- a/dstring.cabal
+++ b/dstring.cabal
@@ -1,12 +1,12 @@
 Name:               dstring
-Version:            0.3
+Version:            0.3.0.1
 Synopsis:           Difference strings.
 Description:
-  Difference strings: a data structure for O(1) append on
-  strings. Note that a DString is just a newtype wrapper around a
-  'DList Char'.  The reason we need a new type instead of just a type
-  synonym is that we can have an 'instance IsString DString' so we can
-  write overloaded string literals of type DString.
+  Difference strings: a data structure for O(1) append on strings. Note that a
+  DString is just a newtype wrapper around a 'DList Char'. The reason we need a
+  new type instead of just a type synonym is that we can have an 'instance
+  IsString DString' without using language extensions (TypeSynonymInstances or
+  FlexibleInstances) so we can write overloaded string literals of type DString.
 Category:      	    Data
 License:       	    BSD3
 License-file:  	    LICENSE
@@ -24,7 +24,7 @@
 
 Library
   Build-Depends:     base == 4.*
-                   , dlist == 0.*
-                   , to-string-class == 0.*
+                   , dlist >= 0.5 && < 0.6
+                   , to-string-class >= 0.1.2 && < 0.2
   Exposed-modules: Data.DString
   Ghc-options:     -O2 -Wall