When iOS devices are using VPP for app deployment, the apps are not being updated regularly on deployed devices.
ZENworks Configuration Management 2020 Update 1 and newer
When using the Volume Purchase Program (VPP) for app deployment to iOS devices, updates to the deployed apps are not being pushed out when new versions of the apps become available.
A setting introduced in ZENworks 2020 Update 1 allows for updates to be identified and deployed. This setting must be enabled. In addition, the VPP Subscription must be run to identify that updates are available.