How to manually upgrade and existing application running as the default ap

Use the web interface

Go To 'Apps'

First you need to stop the existing version of the app running as default:

For the app named 'IoTCoreDefaultApp' select 'Set as Default App'

Wait a few seconds if needed for the message box confirming the new app will run from boot.  The existing version of your app will now have been shutdown.

Now delete the existing version of your app by clicking the 'bin' icon next to it.

Now install the new version in the 'Install App' section:

'App package' – Select "ProjectName_#.#.#.#_arm.appxbundle"

'Certificate' – Select 'ProjectName_#.#.#.#_arm.cer'

Dependency – Press 'Add dependency' and add each of the files in the "/Dependencies" folder

Now press the 'Deploy' > 'Go button'.  The app should be installed without error.  

Once installed it should appear in the 'Apps' list at the top where you can select 'Set as Default App'.  The app will then be run.