--- a/xmonad.cabal
+++ b/xmonad.cabal
@@ -78,7 +78,7 @@
                    process,
                    unix,
                    utf8-string >= 0.3 && < 1.1,
-                   X11>=1.8 && < 1.9
+                   X11>=1.8 && < 1.10
 
     if true
         ghc-options:        -funbox-strict-fields -Wall
