diff --git a/Casks/abscissa.rb b/Casks/abscissa.rb
index aaf38f85b5d..98a3905709c 100644
--- a/Casks/abscissa.rb
+++ b/Casks/abscissa.rb
@@ -4,6 +4,7 @@ class Abscissa < Cask
 
   url "http://rbruehl.macbay.de/Abscissa/Downloads/Abscissa-#{version}.zip"
   homepage 'http://rbruehl.macbay.de/Abscissa'
+  license :unknown
 
   app 'Abscissa.app'
 end