diff --git a/src/Data/Maybe/Unpacked/Numeric/Int64.hs b/src/Data/Maybe/Unpacked/Numeric/Int64.hs
--- a/src/Data/Maybe/Unpacked/Numeric/Int64.hs
+++ b/src/Data/Maybe/Unpacked/Numeric/Int64.hs
@@ -26,7 +26,7 @@
 import Prelude hiding (Maybe,maybe)
 
 import GHC.Base (build)
-import GHC.Exts (Int#)
+import GHC.Exts (Int64#)
 import GHC.Int (Int64(I64#))
 
 import GHC.Read (Read(readPrec))
@@ -35,7 +35,7 @@
 
 import qualified Prelude as P
 
-data Maybe = Maybe (# (# #) | Int# #)
+data Maybe = Maybe (# (# #) | Int64# #)
 
 instance Eq Maybe where
   ma == mb =
diff --git a/src/Data/Maybe/Unpacked/Numeric/Word128.hs b/src/Data/Maybe/Unpacked/Numeric/Word128.hs
--- a/src/Data/Maybe/Unpacked/Numeric/Word128.hs
+++ b/src/Data/Maybe/Unpacked/Numeric/Word128.hs
@@ -27,7 +27,7 @@
 
 import Data.WideWord (Word128(..))
 import GHC.Base (build)
-import GHC.Exts (Word#)
+import GHC.Exts (Word64#)
 import GHC.Word (Word64(W64#))
 
 import GHC.Read (Read(readPrec))
@@ -36,7 +36,7 @@
 
 import qualified Prelude as P
 
-data Maybe = Maybe (# (# #) | (# Word#, Word# #) #)
+data Maybe = Maybe (# (# #) | (# Word64#, Word64# #) #)
 
 instance Eq Maybe where
   ma == mb =
diff --git a/src/Data/Maybe/Unpacked/Numeric/Word64.hs b/src/Data/Maybe/Unpacked/Numeric/Word64.hs
--- a/src/Data/Maybe/Unpacked/Numeric/Word64.hs
+++ b/src/Data/Maybe/Unpacked/Numeric/Word64.hs
@@ -26,7 +26,7 @@
 import Prelude hiding (Maybe,maybe)
 
 import GHC.Base (build)
-import GHC.Exts (Word#)
+import GHC.Exts (Word64#)
 import GHC.Word (Word64(W64#))
 
 import GHC.Read (Read(readPrec))
@@ -35,7 +35,7 @@
 
 import qualified Prelude as P
 
-data Maybe = Maybe (# (# #) | Word# #)
+data Maybe = Maybe (# (# #) | Word64# #)
 
 instance Eq Maybe where
   ma == mb =
diff --git a/unpacked-maybe-numeric.cabal b/unpacked-maybe-numeric.cabal
--- a/unpacked-maybe-numeric.cabal
+++ b/unpacked-maybe-numeric.cabal
@@ -1,6 +1,6 @@
 cabal-version: 2.2
 name: unpacked-maybe-numeric
-version: 0.1.2.1
+version: 0.1.3.0
 synopsis: maybes of numeric values with fewer indirections
 description:
   This library provides one `Maybe` type per the usual numeric types:
@@ -45,7 +45,7 @@
     Data.Maybe.Unpacked.Numeric.Word128
   hs-source-dirs: src
   build-depends:
-    , base >=4.10.1.0 && <5
+    , base >=4.17.1.0 && <5
     , primitive >= 0.6.4
     , wide-word >= 0.1.0.8 && < 0.2
     , word-compat >= 0.0.4 && <0.1