Downloading and using an old version of for Android 2.3.6 (Gingerbread) is a common request for maintaining older hardware, but there are critical limitations to keep in mind. Official support for Android Gingerbread ended in early 2020, meaning even if you successfully install an older version, the WhatsApp servers may block it from connecting or verifying your phone number. How to Download an Old Version
While you can find and install an APK file compatible with older hardware, the service itself will block access for several reasons: Server-Side Block