I have a multisite (test) installation of WordPress and want to get the posts of every blog. 

After hours, I got the solution for that. But now, I have the merged query and like to sort the posts from each blog by date. Now I get the blog1-posts and after all blog1-posts, I get the blog2-posts.

How to sort the array? Here is the code so far:

    $custom_posts = array();

    $blog_ids = wp_get_sites();

    foreach ($blog_ids as $key=>$current_blog) {

    	switch_to_blog($current_blog['blog_id']);

    	$query = get_posts("posts_per_page=10");

    	$custom_posts = array_merge($custom_posts, $query);

    	restore_current_blog();

    }
    
    //SORT THE $custom_posts BY POST_DATE? HOW? :(
    
    global $post; 

    foreach($custom_posts as $post) : setup_postdata($post);

    <<< theposts >>>.
    .
    endforeach;

I hope this is possible to do.
 
Or is there any better way to reach the goal?