The web version of Gmail has offered an undo send feature for awhile, and now the Android app is getting it, too.
Gmail for Android is getting an undo send feature with version 8.7. The feature was discovered by Android Police, and it works pretty much like you'd expect. After you send an email, you'll see a pop-up at the bottom of your screen that'll say "Sending..." and then "Sent". When your message is sent, there will be an "UNDO" button that you can tap that'll pull the email from your recipient's inbox and let you make whatever changes you need to make.
To get this feature, you'll need to be on version 8.7 or later of the Gmail app for Android. If you've confirmed that you're on that version of the app but you still don't have this feature, you can try force closing the app and see if it'll appear that way.
This is a pretty nifty feature for Gmail, giving you the chance to recall an email that you've sent if you made a mistake or left something out after sending it. It's nice to see the undo sent feature make its way to mobile devices, especially since many people rely on their smartphone for sending email.
Is Gmail's undo sent feature appearing on your Android device?