A. When a virtualized application is started on a typical App-V client, the client checks with the App-V server for updates. If an update to the virtualized application is available, the update is pulled down into the local cache and the updated version of the application is launched.
With App-V for RDS, the local cache is shared between all the users logged onto the Remote Desktop Session Host (RDSH). Update behavior is different for these multi-user environments. The application can't be updated in the App-V cache until there are no active users of the application, which means that to update the application, you need to ensure no users on the RDSH are using the application. You'll probably have to stop users from logging on while the cache is updated.
Another option would be to create a new application and advertise it to users instead of updating the application. This way, users can continue to launch the application and get the updated version while existing users would carry on with the old version until they restart the application. Once everyone is on the new version of the application, you can remove the old one. The one disadvantage to this approach is that, depending on the application, settings could be lost, because the update would be seen as a new application—App-V stored customizations wouldn't be carried over.