WhatsApp’s ‘Delete for Everyone’ feature doesn’t delete media files sent to iPhone users. The feature is only available within 1 hour, 8 minutes, and 16 seconds of sending a message you want to delete. WhatsApp says there is no guarantee that the media (or message) will be permanently deleted. A similar privacy flaw was disclosed in the “delete for Everyone” feature of Telegram messenger earlier this week, which the company patched immediately to keep the feature useful in situations for which it has primarily been designed.
Source: https://thehackernews.com/2019/09/whatsapp-delete-for-everyone-privacy.html