While you can technically install an older APK, using an unsupported version of WhatsApp carries significant risks: About supported operating systems | WhatsApp Help Center

: Before installing, go to your phone's Settings > Security and enable "Unknown Sources" to allow the installation of apps from outside the Play Store.

: Navigate to the WhatsApp Messenger for Android page on Uptodown.

Uptodown provides a "Version History" section that allows you to download older, virus-free APK files specifically for legacy systems.

For users on , the official app from the Google Play Store is no longer compatible. This is why many turn to Uptodown , a major third-party repository that hosts a history of previous APK versions. How to Use Uptodown for Older WhatsApp Versions