I have had nothing but problems since the update approximately a month ago. Yahoo often signs you out of mail unexpectedly. This wasn't a problem before the update, as you could sign out of old logins at any time. You can no longer do this & I can no longer change my password (password change supposedly, solves the problem).

Yahoo has signed me out of mail at least 10 times today.

Yahoo being one of the most user friendly mail systems is no conciliation for it now being one of the LEAST SECURE 🔐.