WhatsApp is working on extending temporary messages by sending text messages with a single reading, that is, they disappear once the recipient has seen them.
The messaging application prepares a new type of temporary or ephemeral message that has already been seen in the beta for Android (version 220.127.116.11), where it is accompanied by a new send button with a padlock.
This new button present in the message composer is the one that indicates to the user that he is going to send a text message that is read once, which means that it disappears from the conversation when the recipient has opened and read it.
If the recipient tries to see it again, a small symbol with the number 1 and a notice that the text has expired will appear in its place, but you can ask the sender to send it again, as collected by the specialized WABEtainfo portal.
This type of temporary message is preceded by an informative page, which indicates that given the private nature with which it has been designed, it is not possible to take a screenshot, copy it, share it with other users or save it.
This is currently a feature under development that is expected to arrive in a future update of WhatsApp for Android, first for users of the beta version.