--- a/old-locale.cabal
+++ b/old-locale.cabal
@@ -31,5 +31,5 @@ Library
     exposed-modules:
         System.Locale
 
-    build-depends: base >= 4.2 && < 4.9
+    build-depends: base >= 4.2 && < 4.10
     ghc-options: -Wall