We previously had a brief discussion with Paul Marcos and the app links teams at Apple about the unpredictable and confusing way app deeplinks interact with the "special" handling of Wikipedia search results and links in iOS 9 and up. With iOS 10 out, and the situation not really improved (it got worse, if anything) we will need to reach out to Apple again and ask for clarifications and potentially file product requests to get a smoother experience.

Specifically:

• if the user has the app installed, and has opted to open our domains in app, that preference should be extended reliably to links from the Today and Spotlight and SIRI results screens. Conversely if the user has the app, but has chosen to open links in Safari, that should also be consistently applied.
• In Spotlight, the Wikipedia app and Wikipedia we results should be de-duped and presented as a single result option.
• In iOS 10 with Spotlight Continuation the special wikipedia box should include the Search in App affordance, just as for other data sources which support continuation.