Open Radar

 
Summary:
The iOS 9 Universal Links feature requires an /apple-app-site-association file to be hosted on the webserver to be associated with the app. If the app is installed prior to upgrading the device to iOS 9, then the app/site association is not correctly updated after the upgrade, resulting in Universal Links not working.

The issue has been widely reported internally at Dropbox.

Steps to Reproduce:
1. Running iOS 8.4 on an iPad Air 2, I installed Dropbox 4.0, Yelp 10.2.1, Quip 4.3 from the App Store. I opened Dropbox once.
2. I performed an OTA upgrade to iOS 9.0.1.
3. I created a test page with the following links and tapped them in Mobile Safari. Dropbox and Yelp did not trigger Universal Links, but Quip did:
    - https://www.dropbox.com/s/terjr1q407u7xzu/3342.jpg
    - https://www.yelp.com/biz/a-tale-ahead-photography-pacifica
    - https://www.quip.com/ 
4. I uninstalled and reinstalled Dropbox, and Universal Links started working. I did the same for Yelp and it started working as well.


Expected Results:
I should not have to delete and reinstall an app to make Universal Links work. It should work immediately after upgrading to iOS 9.

Actual Results:
After upgrading to iOS 9, I had to delete and reinstall apps to trigger the /apple-app-site-association file to be re-downloaded and for the app and site to be associated.

Version:
iOS 9.0.1 (13A404)

Notes:
See attachment for current versions of Dropbox, Yelp, and Quip's apple-app-site-association JSON content.

Configuration:
iPad Air 2 A1566

Attachments:
'attachment.txt', 'aasa-dropbox', 'aasa-quip' and 'aasa-yelp' were successfully uploaded.

===
Decoded apple-app-site-association JSON content for Dropbox, Yelp, and Quip is as follows:

{
	"applinks": {
		"apps": [],
			"details": {
				"8KM394JM3R.com.getdropbox.Dropbox": {
					"paths": [
						"/s/*",
						"/sh/*",
						"/member_link/*",
						"/spri/*",
						"/l/s/*",
						"/l/sh/*",
						"/l/member_link/*",
						"/l/spri/*"
					]
				},
				"XGP696M5GC.com.dropbox.DropboxTest": {
					"paths": [
						"/s/*",
						"/sh/*",
						"/member_link/*",
						"/spri/*",
						"/l/s/*",
						"/l/sh/*",
						"/l/member_link/*",
						"/l/spri/*"
					]
				}
			}
	}
}

{
    "applinks": {
        "apps": [],
        "details": [
                {
                        "appID": "BAES6XU9E4.com.yelp.yelpiphone",
   	 		"paths": [ "/", "/home", "/biz/*", "/search", "/biz_photos/*", "/c/*", "/map/*", "/user_details", "/talk", "/talk/*", "/topic/*", "/events" ]	
	}
        ]
    },
    "webcredentials":{
    	"apps":[
     		 "BAES6XU9E4.com.yelp.yelpiphone"
   	 ]
    }
}

{
    "activitycontinuation": {
        "apps": [
            "FMRT79K8DG.com.quip.Quip",
            "N595V8ZZGS.org.backchannel.Docs"
        ]
    },
    "applinks": {
        "apps": [],
        "details": {
            "FMRT79K8DG.com.quip.Quip": {
                "paths": [
                    "/???????????",
                    "/????????????"
                ]
            },
            "N595V8ZZGS.org.backchannel.Docs": {
                "paths": [
                    "/???????????",
                    "/????????????"
                ]
            }
        }
    }
}

Note: Quip's signed JSON does not pass signature verification, but the JSON is well-formed.