Not all android applications can be downloaded or found on Google
PlayStore, depending on the smartphones compatibility or the apps
availability. The only option left to you is to sideload them on your Android phones to
enjoy their incredible functionality. By default, only applications
downloaded from Google Play Store can automatically be updated or
receive update notifications. So the only option you are left on the
sideloaded apps is to be surfing through the internet for the latest versions when you need a bugfix or added features. Fortunately, the issue of having to download a version now and then is finally over.

Developer rumboalla has created an application that will scour the
internet for you. This app will then give you a notification every time your sideloaded applications has an update. The app download updates from APKPure, APKMirror and even Google Play Store. The app makes it possible for one to easily update all of the unauthorised applications in a few steps as exemplified below in screenshot.

First, download APKUpdater app, hit the Download complete notification
and then click 'Install' when prompted. Adjust Options: You also have
to adjust some of the APKUpdater's settings..

To do that, tap on the gear icon in the
top-right corner. Check the box under the option 'Skip experimental
builds' to make sure the application does not download the alpha or
beta versions and then 'Check for Updates' option. This enables you to
tell the application how frequently you want it to check for updates.

Atthe bottom of the menu, enable additional
application sources. These are sites where the app will occasionally
check for updated version of your sideloaded application.

Update the sideloaded applications with
everything now set up, you can now relax because the application will
check for new versions of your installed applications in the
background. Once it finds an updated, it sends a notification – just
click to proceed. Then select any application that needs to be updated
and you are taken directly to the site where you can easily download
an updated version of this APK. Take the APK, launch it and then tap
'Install' and your sideloaded application will now be running the
newest version in seconds.