diff --git a/wai-handler-hal.cabal b/wai-handler-hal.cabal
index 9c37ec4..dc6f6a5 100644
--- a/wai-handler-hal.cabal
+++ b/wai-handler-hal.cabal
@@ -47,7 +47,7 @@ common opts
 
 common deps
   build-depends:
-    , base                  >=4.12      && <4.19
+    , base                  >=4.12      && <4.21
     , base64-bytestring     >=1.0.0.0   && <1.3
     , bytestring            >=0.10.8    && <0.13
     , case-insensitive      ^>=1.2.0.0