This feature was discovered in the latest version 2.19.275 of WhatsApp Beta for Android.
Developers of the popular WhatsApp messenger often add new convenient features to it. Back in October, there were rumors that WhatsApp was testing a new feature called Disappearing Messages, and now new details have appeared.
This feature was discovered in the latest version 2.19.275 of WhatsApp Beta for Android, after which it became more clear how it works. Over the past couple of months, the function has been finalized. Now users have the opportunity to select the option “Delete messages” and set the time interval: the message can be automatically deleted after 1 hour, day, week, month or a year later.
According to the assumption made by the source WABetaInfo, this function is designed so that correspondence in group chats does not take up too much space in the memory of smartphones.

The “Delete messages” function for group chat is available only to the administrator, but the set parameter will be applied to messages of all participants in the group chat.