Some users find success by manually setting the phone's year back to 2018 or 2019, though this may cause issues with your web browser and other apps.
If you downloaded via computer, use a file hashing tool to check the MD5 or SHA-1 signature against the one listed on the APKMirror page. This ensures the file hasn't been tampered with. On Android 2.3.6, you can use an app like "HashDroid" if available. Download Whatsapp Old Version For Android 2-3-6
Use trusted APK archiving websites like APKMirror or Uptodown. Search specifically for the target version number. Some users find success by manually setting the
: Older versions lack the security protocols and architecture (such as modern encryption and media handling) needed to connect to current WhatsApp servers. On Android 2
https://www.apkmirror.com/apk/whatsapp-inc/whatsapp/whatsapp-2-18-305-release/
Download the .apk file directly to your phone or transfer it from your computer.
Download the target WhatsApp APK (v2.11.x or v2.12.x) using a modern computer or smartphone.