Plugin doesn't work!

This plugin does not work with WP 4.4. The opt in checkbox doesn’t show up and when I finally tweaked the code to get it to show up, it sent all information to Constant Contact whether the user had clicked on the ‘opt in’ checkbox or not. Not good. It also marked all the contacts as ‘implied’ even if they had opted in (they should be ‘express’ if they’ve opted in).