diff --git a/lib/notiffany/notifier/terminal_notifier.rb b/lib/notiffany/notifier/terminal_notifier.rb
index de65ec1..7c355ef 100644
--- a/lib/notiffany/notifier/terminal_notifier.rb
+++ b/lib/notiffany/notifier/terminal_notifier.rb
@@ -17,7 +17,7 @@ class TerminalNotifier < Base
         " on Mac OS X 10.8 and later."
 
       def _supported_hosts
-        %w(darwin)
+        %w(darwin darwin21)
       end
 
       def _gem_name