Many of us use -canOpenURL: in our apps. Common usage include to detect if other apps of ours have been installed by the user, or switch to another app (using -openURL:) to perform a specific task. In iOS 9, -canOpenURL: has been changed to read from a white list of URL schemes specified in your app's Info.plist file.

Note that while -canOpenURL: requires white listing, -openURL: doesn't.

To white list URL schemes, add this to your Info.plist file:

    <key>LSApplicationQueriesSchemes</key>
    <array>
        <string>someappurlscheme1</string>
        <string>someappurlscheme2</string>
        <string>someappurlscheme3</string>
    </array>

Note that you should only include the schemename part of schemename://.

Even if you don't use -canOpenURL: directly in your apps, you may be asked to white list URL schemes when you include certain third party libraries/SDKs.