Use APKPure App
Get Update for WhatsApp old version APK for Android
Check whether new versions are available and also update it.
This app will check and update available version from official WhatsApp website directly, and it also has an notification for you if the new version already available.
In your device, including tablet or smartphone, this app will worked on that. it can check whether new versions are available and also download then update it!
Because official website version release its WhatsApp app will before in play store, so just use this app. it helps your WhatsApp app will update to date.