I got an email early this morning from Apple informing me that an app-specific password will now be required to access iCloud through any apps other than Apple's. This means activating two-factor authentication will now be a requirement if you use any app other than Apple's apps. I know two-factor is safer, but I think this will create confusion for many Apple customers. Hopefully those for whom two-factor would be confusing also don't add iCloud to third-party apps in the first place.
