Error on Subscribe Plugin Fatal error: Call to undefined method Incsub_Subscribe_By_Email_Model::del

When activating the Subscribe plugin and trying to add a field for first and last name I did not see it appear on the page. We had deactivated Subscribe2 first. Does not seem to be a shortcode either. The Widget also shows an error. When I went to Remove the First and Last Name fields it gave this error:
Fatal error: Call to undefined method Incsub_Subscribe_By_Email_Model::delete_subscribers_all_meta() in /home/keystone/public_html/wp-content/plugins/subscribe-by-email/admin/pages/admin-settings-page.php on line 129