PHP5 Version of Existing Package

Hello, I am sure this topic has been discussed before but I can't seem to find a definitive answer anywhere. What are the rules about releasing a PHP5 only version of an existing package? Two of my packages are PHP-GTK packages. When I update them to work with PHP-GTK2, which requires PHP5, it will not be possible to make them backward compatible. When I update Gtk_ScrollingLabel, do I need to create a new package called Gtk_ScrollingLabel2 like we have with PHPUnit and PHPUnit2 or should I release it as Gtk_ScrollingLabel 2.0.0? The new version will be the same API just a slightly different implementation and will require PHP-GTK2 instead of PHP-GTK1. Thanks, -- Scott Mattocks scott@crisscott.com http://www.crisscott.com