Here is the deep dive into what it is like to run this app on aging hardware.

Android running OS 5.0 and newer* iPhone running iOS 15.1 and newer. WhatsApp Help Center About supported devices | WhatsApp Help Center

If your browser is modern enough (or if you use a lightweight browser like Opera Mini), you might be able to use WhatsApp Web, though this is difficult on small screens.

Failure conditions:

to operate. While you can still find legacy APK files on repositories like