If you decide the new look and feel of Yahoo Mail isn't for you, you may be able to switch back to the basic Yahoo Mail for desktop. If you don't see an option to go back to the old Yahoo Mail, it's no longer available for your account.

This is a part of your answer regarding my asking for Switch to Basic Yahoo.

Why isn't the user friendly old BASIC YAHOO available for me ? Explain , and enable me to switch to Basic YAHOO again ! Because of user friendly usage of old Basic Yahoo , I didn't prefer anorther mail so far. If I wouldn't return to Basic Yahoo again , I will re-visit the issue.