Since update to WP and also couple of WPMUDEV plugins the global posting has changed (again).
Initially if I set up user sites to use feed from this address
it did not work, so followed notes on plugin page to use http://yourdomain.com/wp-content/recent-global-posts-feed.php.
This worked ok. Now since the latest update this link no longer works, but when I use this link again http://yourdomain.com/feed/globalpostsfeed?posttype=post it then works on user sites.
Which SHOULD we be using please as this is a pain when you have to change 10+ sites let alone once we have 100+ on the network!