WhatsApp is one of a few messaging platforms that lets you delete a message after you’ve sent it. Skype is another one worth mentioning, though we’re sure that far more people actually use WhatsApp.
The messenger platform introduced the feature back in October of last year and allows someone to delete a message “…for everyone” within 7 minutes of the message being sent. Of course, the recipient(s) would not see the message, but would see a ‘message deleted’ placeholder replace the deleted message.
WhatsApp has quietly updated this time window of which you may delete a message after it is sent. The new window is a quite oddly specific one hour, eight minutes, and sixteen seconds.
A new WhatsApp for iOS update (2.18.31) is available on AppStore.— WABetaInfo (@WABetaInfo) March 8, 2018
It is a bug fixes update, but it has the new “Delete for everyone” limit, that’s 1 hour, 8 minutes and 16 seconds.
The amount is actually equal to 4,096 seconds, which can be achieved by the exponent 2 to the 12th power, so it isn't exactly random. The number is an exponential product of 2 just like: 256, 512, 1024, and 2048, which are simpler for coding purposes.
Math lesson aside, we’re not sure why WhatsApp expanded this window so much. Perhaps some folks take well over an hour to change their minds about sending a message.