events calendar plugin

I can’t seem to filter ascending or descending the order of events displayed. No idea what I’m doing wrong here. The only part of this that seems to work is that the number of items changes if I change the post per page item. Here is my code:

<?php global $post;
	$all_events = tribe_get_events(array(
	'posts_per_page'=>-4,
	'eventDisplay'=>'upcoming',
	'order' => 'DESC'
	));

	foreach($all_events as $post) {
	setup_postdata($post);
	?>