Yes, I do think WhatsApp can be outdated. In fact, it has already happened at least once. Just like any software, updated versions are released and the old versions will usually no longer be supported. For example, in January 2018 many WhatsApp users in India got a message stating, “This version of WhatsApp became obsolete.”
The reason was because support Facebook, which now owns WhatsApp, decided to no longer provide support for phones which were running BlackBerry OS, BlackBerry 10 or Windows Phone 8.0. Also in January 2018, Facebook announced that on February 1, 2020, they will no longer support phones running Apple’s iOS 7.