WhatsApp regularly updates its security protocols and encryption. Because Android 4.4.2 lacks the modern security certificates required by the current WhatsApp infrastructure, the app simply won't "handshake" with the servers. Additionally, the Play Store is designed to only show apps compatible with your specific OS version. Where to Find Older Versions (APKs)
Check the box next to to allow the installation of apps from sources other than the Play Store. Whatsapp For Kitkat 4.4 2 Download Old Version
If the old WhatsApp version becomes too unstable, consider these three solutions: Whatsapp For Kitkat 4.4 2 Download Old Version
Installing an old version requires "Sideloading"—manually downloading an APK and enabling "Unknown Sources" in your settings. While the last compatible version for KitKat is often cited as v2.23.8.77 Whatsapp For Kitkat 4.4 2 Download Old Version