WhatsApp has pulled the plug on Android devices running Android 2.2. Therefore, the devices running Android 2.2 will no longer have access to WhatsApp and users will have to upgrade in order to continue using the service.
The current distribution figures show that 0.1% of Android devices still run Android 2.2 and thus the effect of the shutdown is rather minimal.
The decision to pull the plug on the smartphone is primarily due to the sophistication of WhatsApp and older versions of Android does not offer the capabilities to expand upcoming features and advanced security features such as end-to-end encryption.
In addition to the Android devices, WhatsApp plans to end support on devices running BlackBerry 10 OS, or Nokia S40, or Nokia Symbian S60 later on in 2017.