diff --git a/Data/Attoparsec/ByteString/FastSet.hs b/Data/Attoparsec/ByteString/FastSet.hs
--- a/Data/Attoparsec/ByteString/FastSet.hs
+++ b/Data/Attoparsec/ByteString/FastSet.hs
@@ -34,7 +34,7 @@
 
 import Data.Bits ((.&.), (.|.))
 import Foreign.Storable (peekByteOff, pokeByteOff)
-import GHC.Base (Int(I#), iShiftRA#, narrow8Word#, shiftL#)
+import GHC.Exts (Int(I#), iShiftRA#, narrow8Word#, shiftL#)
 import GHC.Word (Word8(W8#))
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Char8 as B8
diff --git a/Data/Attoparsec/Internal/Fhthagn.hs b/Data/Attoparsec/Internal/Fhthagn.hs
--- a/Data/Attoparsec/Internal/Fhthagn.hs
+++ b/Data/Attoparsec/Internal/Fhthagn.hs
@@ -6,7 +6,7 @@
       inlinePerformIO
     ) where
 
-import GHC.Base (realWorld#)
+import GHC.Exts (realWorld#)
 import GHC.IO (IO(IO))
 
 -- | Just like unsafePerformIO, but we inline it. Big performance gains as
diff --git a/Data/Attoparsec/Text/Buffer.hs b/Data/Attoparsec/Text/Buffer.hs
--- a/Data/Attoparsec/Text/Buffer.hs
+++ b/Data/Attoparsec/Text/Buffer.hs
@@ -48,7 +48,7 @@
 import Data.Text.Internal.Unsafe.Char (unsafeChr)
 import Data.Text.Unsafe (Iter(..))
 import Foreign.Storable (sizeOf)
-import GHC.Base (Int(..), indexIntArray#, unsafeCoerce#, writeIntArray#)
+import GHC.Exts (Int(..), indexIntArray#, unsafeCoerce#, writeIntArray#)
 import GHC.ST (ST(..), runST)
 import Prelude hiding (length)
 import qualified Data.Text.Array as A
diff --git a/attoparsec.cabal b/attoparsec.cabal
--- a/attoparsec.cabal
+++ b/attoparsec.cabal
@@ -1,12 +1,12 @@
 name:            attoparsec
-version:         0.13.2.3
+version:         0.13.2.4
 license:         BSD3
 license-file:    LICENSE
 category:        Text, Parsing
 author:          Bryan O'Sullivan <bos@serpentine.com>
 maintainer:      Bryan O'Sullivan <bos@serpentine.com>, Ben Gamari <ben@smart-cactus.org>
 stability:       experimental
-tested-with:     GHC == 7.0.4, GHC == 7.2.2, GHC == 7.4.2, GHC ==7.6.3, GHC ==7.8.4, GHC ==7.10.3, GHC ==8.0.2, GHC ==8.2.2, GHC==8.4.4, GHC==8.6.5, GHC==8.8.1
+tested-with:     GHC == 7.0.4, GHC == 7.2.2, GHC == 7.4.2, GHC ==7.6.3, GHC ==7.8.4, GHC ==7.10.3, GHC ==8.0.2, GHC ==8.2.2, GHC==8.4.4, GHC==8.6.5, GHC==8.8.1, GHC==8.10.1
 synopsis:        Fast combinator parsing for bytestrings and text
 cabal-version:   >= 1.8
 homepage:        https://github.com/bos/attoparsec
@@ -44,7 +44,7 @@
                  containers,
                  deepseq,
                  scientific >= 0.3.1 && < 0.4,
-                 transformers,
+                 transformers >= 0.2 && (< 0.4 || >= 0.4.1.0) && < 0.6,
                  text >= 1.1.1.3
   if impl(ghc < 7.4)
     build-depends:
@@ -53,7 +53,7 @@
   if !impl(ghc >= 8.0)
     -- Data.Semigroup && Control.Monad.Fail are available in base-4.9+
     build-depends: fail == 4.9.*,
-                   semigroups >=0.16.1 && <0.19
+                   semigroups >=0.16.1 && <0.20
 
   exposed-modules: Data.Attoparsec
                    Data.Attoparsec.ByteString