Yahoo! Mail is Yahoo's free email service. It also provides address books, calendars and task lists.
Yahoo! now uses OAuth by default, which is not supported by DAVdroid. To use Yahoo! with DAVdroid, log into your Yahoo! account, go to "Account info" / Account security and enable "Allow apps that use less secure sign in".
CalDAV URL: https://caldav.calendar.yahoo.com
User name and password: Yahoo! email address / password
CardDAV URL: https://carddav.calendar.yahoo.com/dav/
Contact group method: groups are per-contact categories
Yahoo! CardDAV does not work reliably. For instance, when DAVdroid fetches a single contact, Yahoo returns "406 Not accepted".