Why does whatsapp not work in your iPhone 4?

WhatsApp no longer supports iphone 4 because the app requires a minimum of iOS 10, while the iphone 4 can only be updated to iOS 9.3.6. This means that users with an iphone 4 cannot download the latest versions of WhatsApp or receive updates, resulting in compatibility issues. Additionally, older devices may not have the necessary hardware capabilities to run newer app features effectively.