diff --git a/bytestring-builder.cabal b/bytestring-builder.cabal
--- a/bytestring-builder.cabal
+++ b/bytestring-builder.cabal
@@ -1,5 +1,5 @@
 name:                bytestring-builder
-version:             0.10.6.0.0
+version:             0.10.8.1.0
 synopsis:            The new bytestring builder, packaged outside of GHC
 description:
   This is the bytestring builder that is debuting in bytestring-0.10.4.0, which
@@ -51,7 +51,7 @@
 source-repository this
   type:     git
   location: http://github.com/lpsmith/bytestring-builder
-  tag:      v0.10.6.0.0
+  tag:      v0.10.8.1.0
 
 Flag bytestring_has_builder
   default: True
diff --git a/src/Data/ByteString/Builder/ASCII.hs b/src/Data/ByteString/Builder/ASCII.hs
--- a/src/Data/ByteString/Builder/ASCII.hs
+++ b/src/Data/ByteString/Builder/ASCII.hs
@@ -85,7 +85,7 @@
 import           Foreign
 
 
-#if defined(__GLASGOW_HASKELL__) && defined(INTEGER_GMP)
+#if defined(INTEGER_GMP)
 
 #if !(MIN_VERSION_base(4,8,0))
 import           Data.Monoid (mappend)
@@ -304,7 +304,7 @@
 -- Fast decimal 'Integer' encoding.
 ------------------------------------------------------------------------------
 
-#if defined(__GLASGOW_HASKELL__) && defined(INTEGER_GMP)
+#if defined(INTEGER_GMP)
 -- An optimized version of the integer serialization code
 -- in blaze-textual (c) 2011 MailRank, Inc. Bryan O'Sullivan
 -- <bos@mailrank.com>. It is 2.5x faster on Int-sized integers and 4.5x faster
diff --git a/src/Data/ByteString/Builder/Internal.hs b/src/Data/ByteString/Builder/Internal.hs
--- a/src/Data/ByteString/Builder/Internal.hs
+++ b/src/Data/ByteString/Builder/Internal.hs
@@ -130,11 +130,13 @@
 
 import           Control.Arrow (second)
 
+#if MIN_VERSION_base(4,9,0)
+import           Data.Semigroup (Semigroup((<>)))
+#endif
 #if !(MIN_VERSION_base(4,8,0))
 import           Data.Monoid
-import           Control.Applicative (Applicative(..))
+import           Control.Applicative (Applicative(..),(<$>))
 #endif
-import           Control.Applicative ((<$>))
 
 import qualified Data.ByteString               as S
 import qualified Data.ByteString.Internal      as S
@@ -400,11 +402,21 @@
 append :: Builder -> Builder -> Builder
 append (Builder b1) (Builder b2) = Builder $ b1 . b2
 
+#if MIN_VERSION_base(4,9,0)
+instance Semigroup Builder where
+  {-# INLINE (<>) #-}
+  (<>) = append
+#endif
+
 instance Monoid Builder where
   {-# INLINE mempty #-}
   mempty = empty
   {-# INLINE mappend #-}
+#if MIN_VERSION_base(4,9,0)
+  mappend = (<>)
+#else
   mappend = append
+#endif
   {-# INLINE mconcat #-}
   mconcat = foldr mappend mempty
 
@@ -490,21 +502,18 @@
   pure x = Put $ \k -> k x
   {-# INLINE (<*>) #-}
   Put f <*> Put a = Put $ \k -> f (\f' -> a (\a' -> k (f' a')))
-#if MIN_VERSION_base(4,2,0)
   {-# INLINE (<*) #-}
   (<*) = ap_l
   {-# INLINE (*>) #-}
   (*>) = ap_r
-#endif
 
 instance Monad Put where
   {-# INLINE return #-}
-  return x = Put $ \k -> k x
+  return = pure
   {-# INLINE (>>=) #-}
   Put m >>= f = Put $ \k -> m (\m' -> unPut (f m') k)
   {-# INLINE (>>) #-}
-  (>>) = ap_r
-
+  (>>) = (*>)
 
 -- Conversion between Put and Builder
 -------------------------------------
diff --git a/src/Data/ByteString/Builder/Prim/Binary.hs b/src/Data/ByteString/Builder/Prim/Binary.hs
--- a/src/Data/ByteString/Builder/Prim/Binary.hs
+++ b/src/Data/ByteString/Builder/Prim/Binary.hs
@@ -83,7 +83,7 @@
 -- | Encoding 'Word16's in big endian format.
 {-# INLINE word16BE #-}
 word16BE :: FixedPrim Word16
-#ifdef WORD_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 word16BE = word16Host
 #else
 word16BE = fixedPrim 2 $ \w p -> do
@@ -94,7 +94,7 @@
 -- | Encoding 'Word16's in little endian format.
 {-# INLINE word16LE #-}
 word16LE :: FixedPrim Word16
-#ifdef WORD_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 word16LE = fixedPrim 2 $ \w p -> do
     poke p               (fromIntegral (w)              :: Word8)
     poke (p `plusPtr` 1) (fromIntegral (shiftr_w16 w 8) :: Word8)
@@ -105,7 +105,7 @@
 -- | Encoding 'Word32's in big endian format.
 {-# INLINE word32BE #-}
 word32BE :: FixedPrim Word32
-#ifdef WORD_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 word32BE = word32Host
 #else
 word32BE = fixedPrim 4 $ \w p -> do
@@ -118,7 +118,7 @@
 -- | Encoding 'Word32's in little endian format.
 {-# INLINE word32LE #-}
 word32LE :: FixedPrim Word32
-#ifdef WORD_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 word32LE = fixedPrim 4 $ \w p -> do
     poke p               (fromIntegral (w)               :: Word8)
     poke (p `plusPtr` 1) (fromIntegral (shiftr_w32 w  8) :: Word8)
@@ -134,7 +134,7 @@
 -- | Encoding 'Word64's in big endian format.
 {-# INLINE word64BE #-}
 word64BE :: FixedPrim Word64
-#ifdef WORD_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 word64BE = word64Host
 #else
 #if WORD_SIZE_IN_BITS < 64
@@ -170,7 +170,7 @@
 -- | Encoding 'Word64's in little endian format.
 {-# INLINE word64LE #-}
 word64LE :: FixedPrim Word64
-#ifdef WORD_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 #if WORD_SIZE_IN_BITS < 64
 word64LE =
     fixedPrim 8 $ \w p -> do
diff --git a/src/Data/ByteString/Builder/Prim/Internal/UncheckedShifts.hs b/src/Data/ByteString/Builder/Prim/Internal/UncheckedShifts.hs
--- a/src/Data/ByteString/Builder/Prim/Internal/UncheckedShifts.hs
+++ b/src/Data/ByteString/Builder/Prim/Internal/UncheckedShifts.hs
@@ -18,7 +18,7 @@
 -- These functions are undefined when the amount being shifted by is
 -- greater than the size in bits of a machine Int#.-
 --
-#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
+#if !defined(__HADDOCK__)
 #include "MachDeps.h"
 #endif
 
@@ -32,7 +32,7 @@
   ) where
 
 
-#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
+#if !defined(__HADDOCK__)
 import GHC.Base
 import GHC.Word (Word32(..),Word16(..),Word64(..))
 
@@ -70,19 +70,12 @@
 shiftr_w w s = fromIntegral $ (`shiftr_w64` s) $ fromIntegral w
 #endif
 
-#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
+#if !defined(__HADDOCK__)
 shiftr_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftRL#`   i)
 shiftr_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftRL#`   i)
 
 #if WORD_SIZE_IN_BITS < 64
 shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL64#` i)
-
-#if __GLASGOW_HASKELL__ <= 606
--- Exported by GHC.Word in GHC 6.8 and higher
-foreign import ccall unsafe "stg_uncheckedShiftRL64"
-    uncheckedShiftRL64#     :: Word64# -> Int# -> Word64#
-#endif
-
 #else
 shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL#` i)
 #endif
diff --git a/src/Data/ByteString/Short/Internal.hs b/src/Data/ByteString/Short/Internal.hs
--- a/src/Data/ByteString/Short/Internal.hs
+++ b/src/Data/ByteString/Short/Internal.hs
@@ -40,6 +40,9 @@
 
 import Data.Typeable    (Typeable)
 import Data.Data        (Data(..), mkNoRepType)
+#if MIN_VERSION_base(4,9,0)
+import Data.Semigroup   (Semigroup((<>)))
+#endif
 import Data.Monoid      (Monoid(..))
 import Data.String      (IsString(..))
 import Control.DeepSeq  (NFData(..))
@@ -131,9 +134,18 @@
 instance Ord ShortByteString where
     compare = compareBytes
 
+#if MIN_VERSION_base(4,9,0)
+instance Semigroup ShortByteString where
+    (<>)    = append
+#endif
+
 instance Monoid ShortByteString where
     mempty  = empty
+#if MIN_VERSION_base(4,9,0)
+    mappend = (<>)
+#else
     mappend = append
+#endif
     mconcat = concat
 
 instance NFData ShortByteString where
@@ -152,11 +164,7 @@
   gfoldl f z txt = z packBytes `f` (unpackBytes txt)
   toConstr _     = error "Data.ByteString.Short.ShortByteString.toConstr"
   gunfold _ _    = error "Data.ByteString.Short.ShortByteString.gunfold"
-#if MIN_VERSION_base(4,2,0)
   dataTypeOf _   = mkNoRepType "Data.ByteString.Short.ShortByteString"
-#else
-  dataTypeOf _   = mkNorepType "Data.ByteString.Short.ShortByteString"
-#endif
 
 ------------------------------------------------------------------------
 -- Simple operations