When does the App Icon show up?

In my iOS App project, there is an App Icon section, with space for many icons.
All of these icon slots are filled.

But in the simulator, no icon ever appears.
I’m slowly working through the ‘Submit to App Store’ process, but I don’t want this to get rejected due to a missing icon.
Will it ‘magically’ appear when I build for App Store?

It should appear in the simulator. What happens if you deploy to a device?

Same. I just get the spider-web black and white thing.

None of the icon slots is displaying any warnings

Examining the package contents I see icon names that may not directly reflect the icon edit screen, but which are:

So, Xojo 2017 doesnt know about all the icons needed these days.
Starting a project in 2018 (I do have a licence for it) , adding icons to that (there are more), then dragging the icon set to the 2017 edition seems to have sorted the problem out.
I cant see the extra icons in the 2017 IDE but the build went OK and the simulator shows and icon now