According to the documentation we're supposed to move away from custom url schemes. Does this mean that replacing the content of <meta property="al:ios:url" content="applinks://docs" /> to a universal link <meta property="al:ios:url" content="http://www.example.com/about> will work? Will similar substitutions in other schemas work as well?
Universal Links in Web Markup
Applinks and twitter cards' markup are their own thing and I haven't seen either comment on changes for iOS 9. I would wait until they say something before you change it. The custom URL schemes you setup for your app could still be used by JavaScript to check availability since to my knowledge js will have no way to know if a link is a "universal link"
As far as native apps knowing your app is installed the options are now pretty limited unless there is a predefined relationship you setup in your plist because canOpenURL now returns NO for anything not found under the new LSApplicationQueriesSchemes key.
Thank you, aprato.
We want to move away from the custom URL schemes.
So just to confirm, there is no meta property that can be set for a mobile deep link on a web page that will provide the link set in that property to the app?
Well there is always smart app banners. They now want you to use the universal link for that but it has the App Store ID (as do some of the other meta schemes) but that doesn't give you any way to open the app. The smart app banner open/download logic is all controlled by Apple. The best the rest of us can do with an App Store ID is send someone to the download page.
While I'm sure Apple wants to "move away from the custom URL schemes." They are still acknowledging that the other schemes like Twitter cards and Applinks use custom URL schemes. I think the custom schemes are ok for the time being, especially if you support pre 9. I say that because even the new web markup validation tool acknowledges them:
https://search.developer.apple.com/appsearch-validation-tool