It's Friday evening, you're working a bit after closing time and you've got to send out one last email to a contact at another company. There's no chance anybody is still at the office, nor will anybody be in before Monday. You can live with waiting that long, but you know that sending the email right now means it will surely get buried behind everything else that comes in over the weekend, and if the backlog is too long, your message may not even be read until later in the week. The obvious answer is that you should just schedule your email to be sent early Monday morning... And that's when you realize Gmail doesn't actually offer scheduling. Well, it doesn't yet, but Google will be changing that soon.
Disclaimer: Teardowns are based on evidence found inside of apks (Android's application package) and are necessarily speculative and usually based on incomplete information. It's possible that the guesses made here are wrong or inaccurate. Even when predictions are correct, there is always a chance that products could change or may be canceled. Much like rumors, nothing is certain until it's officially announced and released.
The features discussed below are probably not live yet, or may only be live for a small percentage of users. Unless stated otherwise, don't expect to see these features if you install the apk. All screenshots and images are real unless otherwise stated, and images are only altered to remove personal information.
Email scheduling is one of those features you probably assume should be there until the first time you try to use it, then it comes as a small shock when there's no way to do it. People have asked about it in the forums, there are countless browser extensions that implement it in their own way, and if you don't mind a bit of setup, there's even a fairly industrious workaround involving Google Sheets and Google Scripts that works even if you're disconnected when the message needs to be sent.
But all of that shouldn't be necessary for much longer, the Gmail team appears to be adding its own native scheduling feature to the app, and that likely means it should also be coming to the web interface soon.
The evidence is very straightforward on this one, there's just a label containing the title "Schedule send" that goes with a new entry in the overflow menu of the Compose screen.
excerpt from /menu/compose_menu.xml <itemandroid:enabled="false"android:id="@+id/schedule_send"android:visible="false"android:title="@string/menu_schedule_send"android:showAsAction="never"/>
Both the web interface and app will probably launch support for scheduling at the same time. However, there's nothing in here to suggest when we can expect to see that happen. It could come as early as this week, or it might be a few months. But seeing as I have wanted to delay at least a handful of emails in the last two weeks, I can say I'm eager to see this launch as soon as possible.
The APK is signed by Google and upgrades your existing app. The cryptographic signature guarantees that the file is safe to install and was not tampered with in any way. Rather than wait for Google to push this download to your devices, which can take days, download and install it just like any other APK.