3.8.16-8 is now released. Please update right away as I've fixed a regression I've introduced in the previous update that killed the UI(if rebooted or rockstor-pre service restarted). It's a simple nginx configuration error, but it looks like a major problem.
My thanks and apologies to @phillxnet and @Flyer who came to the rescue of users swiftly. You are the heroes of our community!
For those of you running 3.8.16-7 and no UI, you'll have to update via the terminal. Please follow these steps
systemctl restart rockstor-pre rockstor rockstor-bootstrap