[phenomenon]

To update this, you need to add the line of code to about line 493.

I had troubles searching for the line above, here it is again.

search for:

$event['title'] =  htmlspecialchars_uni($event['title']);

and after add

// Start Hack custom field on calendar month view (MarcoH64) 
                            $customfield=unserialize($event['customfields']); 
// End Hack custom field on calendar month view (MarcoH64)