[Plugin: Subscribe2] Notifications for Custom Taxonomies not impelmented!?

Plugin subscribe2, version 8.1

You are able to subscribe to custom taxonomies as described in:
https://subscribe2.wordpress.com/2011/06/06/subscribe2-and-custom-taxonomy-types/

function my_taxonomy_types($taxonomies) {
	// where 'my_taxonomy_type' is the name of your custom taxonomy
	$taxonomies[] = 'my_taxonomy_type';
	return $taxonomies;
}
add_filter('s2_taxonomies', 'my_taxonomy_types');

But this does not mean you will get any notficitaions:
The plugin does not care for subscribed custom taxonomies.

Have a look into code:
https://plugins.svn.www.ads-software.com/subscribe2/tags/8.1/classes/class-s2-core.php
method publish(), line 468,
only default category terms are checked:
$post_cats = wp_get_post_categories($post->ID);