Hi! Have you tried downloading the latest version of WhatsApp from a reliable third-party app store like APKPure or APKMirror? These stores usually have the latest versions of WhatsApp available for download.
Alternatively, you can also try downloading the APK file for WhatsApp from the official website and installing it manually. Note that you may need to enable the installation of apps from unknown sources in your device's settings to do this.
If these methods don't work, you may need to check if your device is compatible with the latest version of WhatsApp. Some older devices may not be able to run the latest versions of the app due to hardware or software limitations.
I hope this helps! Let me know if you have any other questions.