diff --git a/Casks/sizeup-x11.rb b/Casks/sizeup-x11.rb
index b821db3f9..2aa652236 100644
--- a/Casks/sizeup-x11.rb
+++ b/Casks/sizeup-x11.rb
@@ -1,4 +1,4 @@
-class SizeupX11 < Cask
+cask :v1 => 'sizeup-x11' do
   version :latest
   sha256 :no_check