WhatsApp officially ended support for Android 4.1.2 (Jelly Bean) on . Devices running this version can no longer use the app normally and will receive a notification stating that the operating system is no longer supported. Current Official Support
If you are attempting to revive an old device, you can find historical APK files on third-party repositories. However, these versions often fail to verify phone numbers because Meta disables older communication protocols for security. WhatsApp Messenger (Android 4.1+) APKs - APKMirror whatsapp messenger apk android 4.1.2