On October 12, WABetaInfo reported that WhatsApp was gradually rolling out scheduled messages to some testers of Android beta 2.26.40.7. Having the compatible build does not guarantee access: the feature is reaching only some beta accounts. WABetaInfo
What you can schedule
The reported feature works in individual and group chats. It supports text, links, photos and videos, with delivery times ranging from 10 minutes to two weeks ahead. To schedule a message, compose it and tap and hold the send button to choose a time.
WABetaInfo says a scheduled message can be delivered at the chosen time even when the sender’s device is offline or WhatsApp is closed. The feature is also reported to be compatible with end-to-end encryption.
Managing scheduled messages
A dedicated section in the chat information screen lets the sender review and manage pending messages, or delete one before it is sent. WABetaInfo reports that recipients are not notified when a scheduled message is deleted and cannot see that it had been scheduled.
There are two practical limits for group and media sends: each scheduled item can contain one photo or one video, and a scheduled group message goes only to people who were members when it was scheduled. Anyone who joins the group later will not receive it.
