I have searched around SO and other places. I have only found older versions of this answer that don't seem to work any more, and tons of other stuff that isn't even relevant in the latest version.
Long story short, we have a developer providing an IPA to us, who doesn't want to join our developer group. I told him to send us an unsigned IPA, but we couldn't get it figured out based on our old process.
Has anyone done this yet, and would you mind sharing your method with the world?
I ended up finding a working solution for xcode 8. Here is the step by step