TrollStore (highly recommended, requires jailbreak or specific iOS versions) or AltStore for sideloading. An Apple ID. Methods to Install WhatsApp on iOS 9.3.5
You may be able to download the "last compatible version" from your Purchased tab if you have previously owned the app, but it likely will not function after installation. whatsapp ipa for ios 9.3.5 download
If your device is jailbroken with Phoenix, you can bypass Apple's 7-day signing limit entirely. Open on your jailbroken iOS 9.3.5 device. Add the Karen's Repo source ( https://akemi.ai ). Find and install AppSync Unified . TrollStore (highly recommended