Tell me the one who sent you the mail (His email address)
i think it's a scam as i haven't heard of anything like that
I received the same message. Seems like it might be a phishing attempt. Here is who sent it and text of message:
Dear Valued User,
Your Mail version is outdated,
Failure to Upgrade to the newest Yahoo Mail 7.1 now will result to a permanent account closure.
To upgrade click the link below and accept our new terms and conditions.
-- It then includes a link that it tells you to click. I didn't
That is a phishing scam. Ignore and delete it.
Users cannot update anything Yahoo automatically updates all accounts if there is a system upgrade
You can tell it's not from Yahoo
ALL emails from Yahoo concerning your account ALWAYS address you by your first name in the first line of any message -- i.e. Dear Tessy. They NEVER address you by email address, no greeting at all, or a generic greeting like Dear User, Dear Valued Customer, etc
Mark as Spam and Delete
If you already clicked that link immediately run a virus scan AND malwarebytes