diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.markdown
@@ -0,0 +1,4 @@
+0.3.8
+-----
+* Performance tweaks
+* bytestring-in-base flag default to False
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
@@ -1,4 +1,7 @@
-{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances #-}
+{-# LANGUAGE CPP, MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 --
 -- |
 -- Module      :  Codec.Binary.UTF8.Generic
diff --git a/Codec/Binary/UTF8/String.hs b/Codec/Binary/UTF8/String.hs
--- a/Codec/Binary/UTF8/String.hs
+++ b/Codec/Binary/UTF8/String.hs
@@ -1,3 +1,7 @@
+{-# LANGUAGE CPP #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 --
 -- |
 -- Module      :  Codec.Binary.UTF8.String
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
@@ -1,3 +1,7 @@
+{-# LANGUAGE CPP, BangPatterns #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 --
 -- |
 -- Module      :  Data.ByteString.Lazy.UTF8
@@ -119,26 +123,35 @@
               _ -> (replacement_char, 3)
           _ -> (replacement_char, 2)
       _ -> (replacement_char, 1)
+{-# INLINE decode #-}
 
 
 -- | Split after a given number of characters.
 -- Negative values are treated as if they are 0.
 splitAt :: Int64 -> B.ByteString -> (B.ByteString,B.ByteString)
 splitAt x bs = loop 0 x bs
-  where loop a n _ | n <= 0 = B.splitAt a bs
-        loop a n bs1 = case decode bs1 of
+  where loop !a n _ | n <= 0 = B.splitAt a bs
+        loop !a n bs1 = case decode bs1 of
                          Just (_,y) -> loop (a+y) (n-1) (B.drop y bs1)
                          Nothing    -> (bs, B.empty)
 
 -- | @take n s@ returns the first @n@ characters of @s@.
 -- If @s@ has less than @n@ characters, then we return the whole of @s@.
 take :: Int64 -> B.ByteString -> B.ByteString
-take n bs = fst (splitAt n bs)
+take x bs = loop 0 x bs
+  where loop !a n _ | n <= 0 = B.take a bs
+        loop !a n bs1 = case decode bs1 of
+                         Just (_,y) -> loop (a+y) (n-1) (B.drop y bs1)
+                         Nothing    -> bs
 
 -- | @drop n s@ returns the @s@ without its first @n@ characters.
 -- If @s@ has less than @n@ characters, then we return an empty string.
 drop :: Int64 -> B.ByteString -> B.ByteString
-drop n bs = snd (splitAt n bs)
+drop x bs = loop 0 x bs
+  where loop !a n _ | n <= 0 = B.drop a bs
+        loop !a n bs1 = case decode bs1 of
+                         Just (_,y) -> loop (a+y) (n-1) (B.drop y bs1)
+                         Nothing    -> B.empty
 
 -- | Split a string into two parts:  the first is the longest prefix
 -- that contains only characters that satisfy the predicate; the second
diff --git a/Data/ByteString/UTF8.hs b/Data/ByteString/UTF8.hs
--- a/Data/ByteString/UTF8.hs
+++ b/Data/ByteString/UTF8.hs
@@ -1,3 +1,7 @@
+{-# LANGUAGE CPP #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 --
 -- |
 -- Module      :  Data.ByteString.UTF8
diff --git a/Data/String/UTF8.hs b/Data/String/UTF8.hs
--- a/Data/String/UTF8.hs
+++ b/Data/String/UTF8.hs
@@ -1,3 +1,7 @@
+{-# LANGUAGE CPP #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 --
 -- |
 -- Module      :  Data.String.UTF8
diff --git a/System/Environment/UTF8.hs b/System/Environment/UTF8.hs
--- a/System/Environment/UTF8.hs
+++ b/System/Environment/UTF8.hs
@@ -1,3 +1,7 @@
+{-# LANGUAGE CPP #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 --
 -- |
 -- Module      :  System.Environment.UTF8
diff --git a/System/IO/UTF8.hs b/System/IO/UTF8.hs
--- a/System/IO/UTF8.hs
+++ b/System/IO/UTF8.hs
@@ -1,3 +1,7 @@
+{-# LANGUAGE CPP #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  System.IO.UTF8
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:            0.3.7
+Version:            0.3.8
 Author:             Eric Mertens
 Maintainer:         emertens@galois.com
 License:            BSD3
@@ -13,8 +13,11 @@
 Category:           Codec
 Build-type:         Simple
 cabal-version:      >= 1.2
+Extra-Source-Files: CHANGELOG.markdown
 
+
 flag bytestring-in-base
+  default: False
 
 library
   Ghc-options:        -W -O2
@@ -23,7 +26,7 @@
     build-depends: base >= 2.0 && < 2.2
     cpp-options: -DBYTESTRING_IN_BASE
   else
-    build-depends: base < 2.0 || >= 3, bytestring >= 0.9
+    build-depends: base >= 3 && < 4.8, bytestring >= 0.9
 
   Extensions:         CPP
   Exposed-modules:    Codec.Binary.UTF8.String