Just received this update and it finally includes the ability to detect sleep that was updated on the BT version ages ago. Haven't explored other new features yet.
I tested it for a nap. And it correctly showed I was asleep for an hour. It didn't require any setting changes, but I had been using an old Gear Fit. So you may have to designate the S2 for sleep in your S-Health settings on your phone.
I was just looking for sleep info on my watch as I got the update last week. I didn't see anything on the watch....Where can I find this?