ubiquity upgrade option

[Brian Murray]

Due to http://launchpad.net/bugs/1756862 the Ubuntu Foundations team has
decided to disable the option in ubiquity to upgrade from one release to
another. I noticed that testcases 1498 and 1636 both deal with upgrading
using ubiquity. I don't think its necessary to delete these yet (its
possible we may fix it for 18.04.1) but they should be disabled at the
iso.qa.ubuntu.com site.

Can somebody remind me how to do that?

Thanks,
--
Brian Murray