According to reports, Google might be bringing the feature back on Android. Until then, you can use the little app called AppNotifier to get back the Play Store’s app update notification feature again on your Android phone, just like it was before. Download and install the AppNotifier app from the Play Store (link). It is ad-free and weighs below 1MB in size. You don’t need to allow any special permission to the app. The default configuration is sufficient to bring back Play Store’s app update notification on your device. However, if you don’t like the AppNotifier’s notification listening icon on the status bar, you can turn it off from the Apps & Notifications menu on your phone.
