The "undo" function of sending a message via Gmail that existed in the web versions is now also available in the Android version.
This feature allows you to recall an email you just sent. The revocation time you have at your disposal is a few seconds, but enough to press the "Undo" button and the accidental email is not delivered to its destination.
While these errors usually do not happen when you work on a large keyboard like a desktop for example, however, on the small surface of a mobile phone it is very easy to press the wrong button and send an email half-finished.
In addition to version 8.7 of Gmail for Android, you also have the right to appeal on your mobile phone. After sending an e-mail, a black bar will appear at the bottom of the screen with the option "RELEASE", which, unlike the original desktop operation, is enabled by default.
Just press it within 5 seconds and your wrong message will never be delivered to the recipient.