If I upgrade to a new version of the VZAppZone client application, will I lose applications (and content) that I downloaded with a prior version?
No. Content that you download from VZAppZone may be saved either to the device memory or to an SD card so whether you upgrade the VZAppZone client application, or accidentally delete it, all downloaded content safely remains where it was originally stored. Upon performing an upgrade, you will also preserve your personalized VZAppZone settings.