Enterprise application not downloaded
Whether you are using OEM-specific Android+ or Android-Enteprise device agent, the better approach to deploy a private enterprise app wth apk available is to include the .apk file in .pcg package for silent-push/on-demand deployment with a MobiControl profile.
These devices are Android Enterprise.
What we were hoping to be able to do is update the version in the future to update the entire estate.
There are more controsl on what, when and how to upgrade if you use a profile to deploy your enterprise app.
The enterprise app in app-catalog rule is a legacy feature mainly for on-demand deployment in earlier MobiControl versions (v11 or earlier).
I very much echo RC here. You should be using a SOTI Package that encapsulates the APK rather than trying to push it through an App Catalog. SOTI Packages give way more version control and assignment scheduling capabilities than Managed Google Play Private apps or App Catalog Enterprise apps. As long as you always build from the same Package project, increment the package version, increment the APK build version with each compile, and sign the APK using the same mechanism every time, then you can install new versions of the APK on top of each other with direct upgrades with packages.
That's the way we do things currently.
We have 50+ customers set-up and wanted to know if we could update everyone all at once without having to update each profile for each customer as Google Play Store does.