WhatsApp has released a new beta 2.2147.4 update for desktop. The update code suggests that the WhatsApp is now planning to change the time limit for message deletion from 1 hour, 8 minutes, 16 seconds, to 7 days and 8 minutes.

source https://gadgets.ndtv.com/apps/news/whatsapp-desktop-beta-2-2147-4-message-delete-extension-7-days-8-minutes-under-development-2622544#rss-gadgets-all