//Review Page for Gravity Forms
add_filter( 'gform_review_page', 'add_review_page', 10, 3 );
function add_review_page( $review_page, $form, $entry ) {

    // Enable the review page
     $review_page['is_enabled'] = true;
if (1 ==  $form['id'] ) {
//disable for the Email Newsletter Form
$review_page['is_enabled'] = false;
}
    // Populate the review page
     $review_page['content'] = '<p>Please review the information below before submitting the form. If you would like to make any changes use the "Previous" button at the bottom of the page.</p>';
     $review_page['content'] .= GFCommon::replace_variables( '{all_fields}', $form, $entry );

    return $review_page;
 }