Yahoo Mail provides option for changing the sorting order of the email messages based on the date. Users can click on the arrow mark displayed below the Date field.
– This means the messages are displayed descending by date and any new messages will appear in the top. If you want to display the messages in ascending sort order then click on the arrow mark pointing downwards. Now the messages will be displayed in ascending order. But if you want to permanently set the date message order then you can use the mail options. Click on the Options and select Mail Options
Navigate to General tab and using the Message Ordering radio option you can change default message ordering either descending by date or ascending by date.