diff --git a/Formula/byobu.rb b/Formula/byobu.rb
index a3a2ae552cc..feaa738e693 100644
--- a/Formula/byobu.rb
+++ b/Formula/byobu.rb
@@ -2,8 +2,8 @@ require 'formula'
 
 class Byobu < Formula
   homepage 'http://launchpad.net/byobu'
-  url 'http://launchpad.net/byobu/trunk/5.18/+download/byobu_5.18.orig.tar.gz'
-  md5 '5940cef1ae3d750b5712793a90901d67'
+  url 'https://launchpad.net/byobu/trunk/5.21/+download/byobu_5.21.orig.tar.gz'
+  sha1 '81ed721b643addf84c7aba10f173c27dc69391bd'
 
   depends_on 'coreutils'