Google is rolling out the latest update for the Currents app. Or maybe more accurate, Google is in the process of rolling out the final update for the Current app. The update is telling users they should check out Google Play Newsstand. There is a bit of information for existing Currents users, but essentially this is the Currents RIP notice.
If you happen to have a device with the Currents app installed, you should see the notification letting you know an update is available. Once updated, and launched, you will be greeted with a message introducing you to the Newsstand app. Google mentions how this is a "new app where you can enjoy your favorite news, blogs, and (where available) magazines."
Currents users should have a fairly easy transition over. To that point, your current subscriptions will be transferred to Newsstand. And furthermore, at the bottom of the brief message -- there is a one-click option to launch the Google Play Newsstand app. Having said that, once clicked you will be welcomed to the new app, and the new setup.
Once in Newsstand, Google then offers another brief synopsis about how they have combined the two products into a single app. Moving forward you will want to launch the "Play Newsstand" app as opposed to the "Currents" app. Those looking for a bit more about Newsstand can check the Play Store listing for the app.