The option to watch videos for gems is only available to iOS players. And that too will be offered at random. Some will get to watch for 2 gems, some more than 2, some none at all. Boils down to luck. As for notification for newer versions, I don't think S8 has ever had notifications to download newer versions.. Only for android players, sometimes you'll get a pop up to download another game for 6 gems.
Seniors players do correct me if I'm wrong.