public function listener()
 {
     if (isset($_GET['nf-switcher'])) {
         switch ($_GET['nf-switcher']) {
             case 'upgrade':
                 update_option('ninja_forms_load_deprecated', FALSE);
                 nf_fs_upgrade();
                 break;
             case 'rollback':
                 update_option('ninja_forms_load_deprecated', TRUE);
                 nf_fs_downgrade();
                 break;
         }
         header('Location: ' . admin_url('admin.php?page=ninja-forms'));
     }
 }
 public function listener()
 {
     if (!current_user_can(apply_filters('ninja_forms_admin_version_switcher_capabilities', 'manage_options'))) {
         return;
     }
     if (isset($_GET['nf-switcher'])) {
         switch ($_GET['nf-switcher']) {
             case 'upgrade':
                 update_option('ninja_forms_load_deprecated', FALSE);
                 nf_fs_upgrade();
                 break;
             case 'rollback':
                 update_option('ninja_forms_load_deprecated', TRUE);
                 nf_fs_downgrade();
                 break;
         }
         header('Location: ' . admin_url('admin.php?page=ninja-forms'));
     }
 }