Well it doesn't work anymore, at least for me. Wrote about it to apps.splunk.com admins and they told me that they know and were fixing it. But it's a feature I definitely need !
You can navigate to a specific application page on apps.splunk.com and click on the 'subscribe' link. That way you'll get notified when apps you care about are updated.
That button hasn't gone GA yet. Ha.
Thanks... Where is the button to motivate the Splunk developer working on the Exhcnage app to git r done!?!