We've always gotten a little chuckle when press releases try to tell us the precise time an app update will go live in Google Play — it just doesn't work that way. You hit publish, it shows up for folks a couple hours later, more or less. That's changed, starting today. Google has rolled out "timed publishing," allowing developers to choose exactly when an update will go live.
To be clear, this is only for app updates. But it's pretty slick. Developers will push the new apk through like normal, and it'll still take a couple hours for the update to "process." They'll then get a "Go live" button. Once that button is pressed, everyone should see the update available at the same time, "within a few minutes," Google says. (Edit: Google's docs sort of made it sound like you can schedule a time for an update to push — that's not quite the case, it seems. Basically the developer has the option for an update to go live for everyone at one time, but they still have to push the "go live" button.)
There are a few caveats to all this — again, this can't be used for the first time an app is published, and all updates still have that "processing" waiting period, and you can only process one change at a time. You also can't revert changes. So be sure to read through the support docs.
But all in all — at least for developers who take advantage of this feature — it's a good thing. So long to the trollout.