If the 2021 version no longer works (and it likely won't for much longer), consider these alternatives:
When an app like WhatsApp becomes essential for government services, education, and banking, losing support on an older OS effectively "de-platforms" lower-income users from modern society. Summary Checklist for Android 4.4.4 Users whatsapp apkpure android 444 2021
: Consider lighter alternatives like Telegram or Signal , though their support for older Android versions is also rapidly shrinking. If the 2021 version no longer works (and