The application’s performance on iOS is also heavily influenced by Apple’s unique operating system architecture. iOS is known for its strict resource management and "sandboxing" of apps, which isolates applications to prevent them from interfering with one another or the system core. To function within these constraints, WhatsApp leverages Apple’s Push Notification Service (APNs). This system allows WhatsApp to conserve battery life by not constantly running in the background. Instead, the app "sleeps" until the Apple servers ping the device with a new message notification. This symbiotic relationship between the app and the iOS infrastructure ensures that WhatsApp remains efficient without draining the iPhone’s battery, a critical requirement for mobile utility.
Apple forces developers to build apps using newer iOS SDKs (Software Development Kits), which do not compile backward compatibility for 32-bit iOS 10 devices. Workarounds: Can You Make It Work? whatsapp for ios 1033 work