Index: b/unicode-collation.cabal
===================================================================
--- a/unicode-collation.cabal
+++ b/unicode-collation.cabal
@@ -50,7 +50,7 @@ flag executable
   Default:             False
 
 common common-options
-  build-depends:       base >= 4.11 && < 4.20
+  build-depends:       base >= 4.11 && < 4.22
 
   ghc-options:         -Wall
                        -Wcompat
