--- a/tree-monad.cabal
+++ b/tree-monad.cabal
@@ -20,7 +20,7 @@ extra-source-files:  CHANGELOG.md, READM
 library
   exposed-modules:     Control.Monad.SearchTree
   other-extensions:    Rank2Types
-  build-depends:       base >=4.13 && <4.15
+  build-depends:       base >=4.13 && <4.16
   default-language:    Haskell2010
   ghc-options:         -Wall
 
