...from: http://www.macrumors.com/2014/10/08/apple-reminds-app-specific/

Apple Begins Reminding Two-Factor Authentication Users About App-Specific Passwords Wednesday October 8, 2014 8:38 pm PDT by Husain Sumra Apple has begun emailing iCloud users who have enabled two-factor authentication on their Apple IDs, reminding them that application specific passwords will be required when trying to access iCloud data on third party apps starting tomorrow.

[Screen Shot 2014-10-08 at 8.13.42 PM] In addition to the email reminders, Apple last week published a new support documenthttp://support.apple.com/kb/HT6186educating users on how to use app-specific passwords. While the feature was originally intended to require the feature on October 1, it's unclear why two-factor authentication users are being reminded of it a week later.

App-specific passwords are a new feature Apple introduced in mid-Septemberhttp://www.macrumors.com/2014/09/16/apple-app-specific-passwords/, following the launch of two-factor authenticationhttp://www.macrumors.com/2014/09/16/icloud-two-factor-authentication/ for accessing iCloud.comhttp://iCloud.com. The changes arrived after a hacking incident that saw the iCloud accounts of several celebrities compromised due to weak passwords.

CEO Tim Cook has promisedhttp://www.macrumors.com/2014/09/04/cook-security-alerts-icloud/ to improve iCloud security by increasing awareness around Apple's security features like two-factor authentication as well as a sending out email notificationshttp://www.macrumors.com/2014/09/08/icloud-alert-emails-web/ whenever a device is restored, an account is accessed or a password change is attempted.