WhatsApp first introduced the ability to allow you to delete your messages for everyone in the group 5 years ago. Initially there was a time limit of eight minutes but the app tweaked that cut-off time to a more precise 1.1377 hours. Last year there was hint signaling that the app would further expand this limit to three months. The change was not rolled out though presumably because the developers realized the time limit could be too long.
It has been reported that WhatsApp has increased time limit to delete the sent messages to 2 days and 12 hours for some users on latest v2.22.15.8 beta release. It is less arbitrary than the current cut-off of 1 hour, 8 ins and 16 seconds. There is no indicator in WhatsApp beta to notify you about increased limit. You will require to try it for yourself by sending a message to a group and then attempt to delete it after a couple of days. It has also got a feature to let group admins to delete the chats from anyone in the group for other members is also under development.