WP: Notification to Admin or Author upon status change

function.php

<?php 

function authorNotification( $new_status, $old_status, $post ) {
    if ( $new_status == 'publish' && $old_status != 'publish' ) {
        $author = get_userdata($post->post_author);
        $message = "
            Hi ".$author->display_name.",
            New post, ".$post->post_title." has just been published at ".get_permalink( $post->ID ).".
        ";
        wp_mail($author->user_email, "New Post Published", $message);
    }
}
add_action('transition_post_status', 'authorNotification', 10, 3 );

?>