iCloud Adds Support for App-Specific Passwords
If you use iCloud with any third party apps, such as Microsoft Outlook, Mozilla Thunderbird, or BusyCal, you can generate app-specific passwords that allow you to sign in securely, even if the app you’re using doesn’t support two-step verification. Using an app-specific password also ensures that your primary Apple ID password isn’t collected or stored by any third party apps you might use. Starting on October 1, 2014, app-specific passwords will be required to sign in to iCloud using any third party apps.
They’ve also added two-factor authentication for the iCloud.com Web apps and iCloud backup.
