Give the "Send" button WhatsApp is an action that had no turning back: once you sent the message, it would reach its recipient or yes. That could change in a future version of the application that would retrieve the message as if you had never sent.
That's what I said in The Telegraph, which reveal that this function would avoid such problems sending messages that actually wanted not send if we realize after a few seconds of error. If the recipient has not read it yet, you can delete it so you never get to do.
They know where you are at all times
In another equally interesting that option be added: that of being able to send our friends our location in real time and how "we move" so that our contacts can easily meet to stay with them via WhatsApp.
The feature, called Live Location Tracking allows others to see where in a group chat we move. In this option the user can also set how long you want others to see your position: one, two or five minutes.
This is a nice feature added to the location sharing feature, one of the most popular in this application. Among other improvements are reshuffled the ability to respond to status messages or even another option to shake the phone when we are in a conversation to directly contact the service WhatsApp and know you want to charge that user is doing spam.