Custom ROMs: Look into installing a newer version of Android (like LineageOS) on your old hardware to gain access to the official Play Store version.
WhatsApp 4.2.2 APK is an older version of the WhatsApp messaging app, which was released in 2015. The APK file is a package file used by the Android operating system to distribute and install apps. In this case, the WhatsApp 4.2.2 APK file contains the installation package for version 4.2.2 of the WhatsApp app. whatsapp 4.2.2 apk download