diff --git a/zlib/zlib.cabal b/zlib/zlib.cabal
index 59678d9..b2df619 100644
--- a/zlib/zlib.cabal
+++ b/zlib/zlib.cabal
@@ -84,7 +84,7 @@ library
   other-extensions: DeriveGeneric
   other-extensions: CApiFFI
 
-  build-depends:   base >= 4.9 && < 4.21,
+  build-depends:   base >= 4.9 && < 4.22,
                    bytestring >= 0.9 && < 0.13
 
   build-tools:     hsc2hs >= 0.67 && < 0.69