Short answer: Official WhatsApp no longer supports Android 4.4.2 (KitKat). Installing an old APK built for Android 4.4.2 may run initially, but it’s unsafe and unreliable. Use a device with a supported Android version or upgrade Android if possible.
If you are still using a device stuck on Android 4.4.2, your options for staying connected are limited: whatsapp apk for android 442 work