The message removal function, launched in October 2017, was recently extended to let you 'unsend' any message within 68 minutes of submitting it.
Hackers were able to modify the software to further expand this limit, which allowed them to delete messages dating back as long ago as three years.
Now the Facebook-owned firm behind the app has introduced the ability to block such requests, in a bid to counter these illegal deletions.
WhatsApp's 'Delete for Everyone' tool is facing yet another redesign it appears, after code for a tweak to the feature was spotted in an upcoming beta testing release. Modified versions of the software can illegally delete messages dating back as long ago as three years
The code which enables the new feature was spotted by tech blog WABetaInfo and it is unclear how quickly it will be rolled out globally.
Currently, when a ‘Delete for Everyone’ request is submitted, WhasApp matches a unique ID number that's generated as part of the revoke request with the original message and deletes the text if they match.
There were no checks in place to ensure that the date the revoke request was sent matched with the message to be deleted.
This meant that hacked versions of WhatsApp, distributed via third party sites rather than the official Google Play store, could be tweaked to allow deletion of older messages sent via the service.
In the updated version, the tool will also check the timestamp of the original message, to make sure that the revoke request was sent within 24 hours of it being received.
If the message was received more than 24 hours before the revoke request, it won't be removed.
This 24 hour period was chosen to maximise the chances that a recipient of a revoke request will receive it in time, accounting for issues like their phone being off or out of battery at the time the request was initially sent.
WhatsApp will soon give you more time to unsend embarrassing messages. The app currently allows users to recall messages up to seven minutes after they have been sent as part of its 'Delete for Everyone' tool. That time window could soon be extended to 24 hours
This means that if a recipient of a 'Delete for Everyone' request doesn't turn their phone on within 24 hours, the original message won't be deleted, according to WABetaInfo.
Writing on Twitter, a spokesman for the site said: 'WhatsApp silently adds some protections to block invalid revoke requests, for iOS, Android and Windows Phone users.'
Messages that are recalled are replaced with a 'this was deleted' message.
There's still a chance a user will have seen an opened message before you've had a chance to recall it.
WhatsApp's FAQ page explains how sent messages can be deleted.
It says: 'Deleting messages for everyone allows you to delete specific messages you have sent to either a group or an individual chat.
'This is particularly useful if you sent a message to the wrong chat or if the message you sent contains a mistake.'
After its initial launch last year, the option to delete sent messages was well-received.
Its only shortcoming, in the opinion of users, was the seven minute time limit.
As a result, the original 420 seconds (seven minutes) window was then broadened to 4,096 seconds (68 minutes and 16 seconds).
The new 24 hour window, once it's rolled out to all users, will work for all WhatsApp messages, including: GIFs, files, locations and videos.
To delete a message, open WhatsApp and go to the chat containing the message you want to delete.
Tap and hold the message, then choose Delete from the menu.
Tap 'Delete for everyone' and the message will disappear.
Messages you successfully delete for everyone will be replaced with 'This message was deleted' in your recipients' chats.
After that deadline, WhatsApp users are only able to delete the message from their own device.
Other recipients in the chat will still be able to see the message.
Similarly, if you see 'This message was deleted' in a chat, it means that the sender deleted their message for everyone.
The WhatsApp FAQ added: 'In order for messages to be successfully deleted for everyone, both you and your recipient must be using the latest version of WhatsApp for Android, iPhone or Windows Phone.'
Another worry is that if something goes wrong and the deletion doesn't work, you won't be notified.
The Daily Mail
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