WhatsApp is testing a feature that lets you 'revoke' unread messages you sent prematurely

Soon, you may be able to take back your drunk or needlessly angry texts on WhatsApp.
The Facebook-owned messaging service is reportedly testing the ability to edit or recall messages that have already been sent. This means you can delete or revise a message even after your friend’s phone has technically received it.
The feature only works if the recipient has not read the message yet. On WhatsApp, this is signified by a blue tick mark. If the message has simply been received by a phone but not read — with grey tick marks, in other words — the feature still works.
The feature was first spotted by Twitter account @WABetaInfo, which tracks features that WhatsApp is testing across platforms.
The feature is currently being tested in the beta versions of WhatsApp on Android and iOS. The update adds “revoke” and “edit” options for messages that have not yet been viewed. From the screenshots, it seems like the message is replaced with “Sender revoked the message” — so your friends will know you’re keeping something from them.
WhatsApp is also reportedly testing a feature that may remind you of Snapchat’s “Stories.” It will enhance the current “status” feature, where users can add a picture with a caption or doodle that disappears after 24 hours. Similar to Snapchat and Instagram, users can also reply to each others’ stories.
A third feature being tested right now, called “live location tracking,” allows users to enable other people in a group chat to track their location in real time. The feature seems to be directed at making IRL meetups easier among family and friends.
Mashable.com