I am not familiar with the Application Catalog but rather install Apps directly to Android devices via an APK install Package. The updates can always be performed automatically without user intervention. Do you have a management use case that requires that the end users select apps from a subset of available apps published in the Application Catalog? If not, I would recommend a different enrollment and management style such as Device Administrator with Android+ and an OEM specific SOTI Agent. 

That depends on the device brand/model(s) that you are managing:

1. If there is a corresponding Android+ device agent for your device model, and you have the apk file,  then silent app push to the device is possible by package deployment rule for v12.x or earlier, or by package-within-Android+ profile for v13+. 

2. If you don't have the apk file and the app is only available from Google Play store, but your device support Android-For-Work/Android-Enterprise managed-device mode, then  you can simply create a Managed Google Play account on Google's server within Mobicontrol v13.3+ web-console and manage selected apps (mandatory app entries in app-catalog rule) to be deployed from Managed Google Play store to your device silently.  However, your device has to be factory reset to get it in this Android-For-Work/Android-Enterprise managed-device mode.  An on-line list of supported devices is maintained by Google at https://www.android.com/enterprise/device-catalog/.  Please be warned that some older device models there only support BYOD/work-profile mode, and not the more useful managed-device mode I am talking about here.

3. If your device has no Android+ agent and does not support AFW/AE managed-device mode, then you can only use Generic Android agent and silent push is not possible irrespective of whether you have the apps apk file or not.   However,  you might use file-sync rules with proper options & sync-schedule to fake a SEMI-silent app push (i.e. apk file can be copied over the air to selected directory on the device automatically), but the device end-user will be prompted, once for each app copied, to press "OK" button before actual installation of the apk file gets started.

Newer versions of the same app can then be upgraded in-place (i.e. upgrading only the apps binary without removing/corrupting user's data associated with old app binary in the app's sandboxed directories)  remotely in each of the above 3 cases :

For case 1 : by updating with the right options, the package deployment rule for v12.x or earlier, or the package-within-Android+ profile for v13+. 

For case 2 : Configure the upgrade behavior on your Managed Google Play account (e.g. if automatic upgrade go ahead unconditionally or only when no new permissions added in the newer app version.

For case 3 :  Replace the apk file with a newer version in the source directory of your file-sync rule and then adjust the file-sync rule with the right options.