diff --git a/Codec/Binary/UTF8/Generic.hs b/Codec/Binary/UTF8/Generic.hs
--- a/Codec/Binary/UTF8/Generic.hs
+++ b/Codec/Binary/UTF8/Generic.hs
@@ -1,8 +1,14 @@
 {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances #-}
--- | This module provides fast, validated encoding and decoding functions
---   between 'ByteString's and 'String's. It does not exactly match the
---   output of the Codec.Binary.UTF8.String output for invalid encodings
---   as the number of replacement characters is sometimes longer.
+--
+-- |
+-- Module      :  Codec.Binary.UTF8.Generic
+-- Copyright   :  (c) Iavor S. Diatchki 2009
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  emertens@galois.com
+-- Stability   :  experimental
+-- Portability :  portable
+--
 module Codec.Binary.UTF8.Generic
   ( UTF8Bytes(..)
   , decode
@@ -152,8 +158,8 @@
         case get_follower d1 cs1 of
           Just (d2, cs2) ->
             case get_follower d2 cs2 of
-              Just (d,_) | d >= 0x10000 -> (toEnum d, 4)
-                         | otherwise    -> (replacement_char, 4)
+              Just (d,_) | d >= 0x10000 && d < 0x110000 -> (toEnum d, 4)
+                         | otherwise                    -> (replacement_char, 4)
               _ -> (replacement_char, 3)
           _ -> (replacement_char, 2)
       _ -> (replacement_char, 1)
diff --git a/Data/ByteString/Lazy/UTF8.hs b/Data/ByteString/Lazy/UTF8.hs
--- a/Data/ByteString/Lazy/UTF8.hs
+++ b/Data/ByteString/Lazy/UTF8.hs
@@ -1,4 +1,14 @@
--- | This module provides fast, validated encoding and decoding functions
+--
+-- |
+-- Module      :  Data.ByteString.Lazy.UTF8
+-- Copyright   :  (c) Iavor S. Diatchki 2009
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  emertens@galois.com
+-- Stability   :  experimental
+-- Portability :  portable
+--
+--   This module provides fast, validated encoding and decoding functions
 --   between 'ByteString's and 'String's. It does not exactly match the
 --   output of the Codec.Binary.UTF8.String output for invalid encodings
 --   as the number of replacement characters is sometimes longer.
@@ -104,8 +114,8 @@
         case get_follower d1 cs1 of
           Just (d2, cs2) ->
             case get_follower d2 cs2 of
-              Just (d,_) | d >= 0x10000 -> (toEnum d, 4)
-                         | otherwise    -> (replacement_char, 4)
+              Just (d,_) | d >= 0x10000 && d < 0x110000 -> (toEnum d, 4)
+                         | otherwise                    -> (replacement_char, 4)
               _ -> (replacement_char, 3)
           _ -> (replacement_char, 2)
       _ -> (replacement_char, 1)
diff --git a/Data/ByteString/UTF8.hs b/Data/ByteString/UTF8.hs
--- a/Data/ByteString/UTF8.hs
+++ b/Data/ByteString/UTF8.hs
@@ -1,4 +1,14 @@
--- | This module provides fast, validated encoding and decoding functions
+--
+-- |
+-- Module      :  Data.ByteString.UTF8
+-- Copyright   :  (c) Iavor S. Diatchki 2009
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  emertens@galois.com
+-- Stability   :  experimental
+-- Portability :  portable
+--
+--   This module provides fast, validated encoding and decoding functions
 --   between 'ByteString's and 'String's. It does not exactly match the
 --   output of the Codec.Binary.UTF8.String output for invalid encodings
 --   as the number of replacement characters is sometimes longer.
@@ -103,8 +113,8 @@
         case get_follower d1 cs1 of
           Just (d2, cs2) ->
             case get_follower d2 cs2 of
-              Just (d,_) | d >= 0x10000 -> (toEnum d, 4)
-                         | otherwise    -> (replacement_char, 4)
+              Just (d,_) | d >= 0x10000 && d < 0x110000 -> (toEnum d, 4)
+                         | otherwise                    -> (replacement_char, 4)
               _ -> (replacement_char, 3)
           _ -> (replacement_char, 2)
       _ -> (replacement_char, 1)
diff --git a/Data/String/UTF8.hs b/Data/String/UTF8.hs
--- a/Data/String/UTF8.hs
+++ b/Data/String/UTF8.hs
@@ -1,3 +1,13 @@
+--
+-- |
+-- Module      :  Data.String.UTF8
+-- Copyright   :  (c) Iavor S. Diatchki 2009
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  emertens@galois.com
+-- Stability   :  experimental
+-- Portability :  portable
+--
 {-# LANGUAGE MultiParamTypeClasses, UndecidableInstances #-}
 module Data.String.UTF8
   ( -- * Representation
@@ -35,7 +45,7 @@
 import qualified Codec.Binary.UTF8.Generic as G
 import Codec.Binary.UTF8.Generic (UTF8Bytes)
 
--- | The type of strngs that are represented using tthe UTF8 encoding.
+-- | The type of strngs that are represented using the UTF8 encoding.
 -- The parameters is the type of the container for the representation.
 newtype UTF8 string = Str string deriving (Eq,Ord)   -- XXX: Is this OK?
 
diff --git a/System/Environment/UTF8.hs b/System/Environment/UTF8.hs
--- a/System/Environment/UTF8.hs
+++ b/System/Environment/UTF8.hs
@@ -1,3 +1,15 @@
+--
+-- |
+-- Module      :  System.Environment.UTF8
+-- Copyright   :  (c) Eric Mertens 2009
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer:    emertens@galois.com
+-- Stability   :  experimental
+-- Portability :  portable
+--
+-- Support for UTF-8 based environment manipulation
+--
 module System.Environment.UTF8
   (getArgs, getProgName, getEnv, withArgs, withProgName, getEnvironment)
   where
diff --git a/utf8-string.cabal b/utf8-string.cabal
--- a/utf8-string.cabal
+++ b/utf8-string.cabal
@@ -1,5 +1,5 @@
 Name:               utf8-string
-Version:            0.3.5
+Version:            0.3.6
 Author:             Eric Mertens
 Maintainer:         emertens@galois.com
 License:            BSD3