Whatsapp: For Android 442 Uptodown Full Exclusive

Look into custom ROMs (like LineageOS) on forums like XDA Developers to see if your specific phone model can be unofficially upgraded to Android 5.0 or higher.

If you find that WhatsApp simply will not activate on your Android 4.4.2 device, you are not entirely out of options for communication: whatsapp for android 442 uptodown full