Filter notification of new topic email text to followers

If you have Board Following enabled, you can filter the text of the email that is sent to followers whenever a new topic is posted on a board.

In your functions.php file, or other suitable place, add the following:

/**
 * Filter the notification email text to followers of a board
 * @param $message - the original email content
 * @param $post - the post object for the new topic
 * @board_id - the ID of the board posted on
 */
function your_prefix_notification_email_content( $message, $post, $board_id ) {
  // Add your new message content here
  $message = 'My new message';
  return $message;
}
add_filter( 'ctdb_follower_notification_new_topic_email', 'your_prefix_notification_email_content', 10, 3 );