As per a report by WABetainfo, a platform that tests WhatsApp features in beta and publishes information about them, WhatsApp will not replace the 7 days option and add the 24 hours option. The screenshot shared by the platform shows the 24 hours option in the section where users enable/ disable disappearing messages for personal and group chats.
WhatsApp earlier used to only let admins control Disappearing Messages. Recently, it released an update for iOS that allows all participants in a group to change the Disappearing Messages setting by default. WhatsApp is also testing the ability to bring disappearing photos feature to both Android and iOS platforms.
Additionally, a report said that WhatsApp tested a voice messages playback speed feature on the public beta channel. It was enabled for a few users on WhatsApp for Android beta 220.127.116.11 but was disabled with the release of a new WhatsApp for Android beta 18.104.22.168 update the very next day.