Update side-loaded Android apps with APKUpdater
When you install apps from Google Play, you'll be notified whenever an update is available. If you have opted to side-load apps from other sources, however, this update notification is not available, leaving you having to keep manually checking for new versions.
This is, of course, a massive pain in the derriere, and far too much like hard work. Install APKUpdater, and your side-loaded apps will be kept up to date just like those from more official sources. Here's what you need to know.
The first thing you'll need to do is install the APKUpdater app from Guthub -- as you're using this to keep side-loaded apps updated, there's no need to tell you that you'll need to enable the installation of apps from "Unknown sources" in Security settings. By default, the app scours APKMirror for the availability of new versions of apps you have installed, and this includes potentially unstable experimental builds.
If you would rather stick to non-alpha/beta releases, fire up APKUpdater on your phone or tablet and click the cog button. Check the option labelled "Skip experimental builds" and you'll only be notified about stable releases. While you're here, you can also adjust the update checking schedule from daily to weekly if you like, or disable automatic checking if you would prefer to manually check from time to time.
You can also opt to look in the Play Store for updates as well as APKPure. Experiment, and see which options work best for you.