Is this an authentic Yahoo.com email?

That's nothing but an outright scam. Whatever you do, avoid clicking on the links or attachments in the message and giving out your personal information to the scammers. You could risk getting your account hijacked in the process if you do so, and maybe put in viruses or malware on your computer. Get that message spammed straight into oblivion right away. Yahoo doesn’t ever send you unsolicited emails to request for your personal information, as they already have that stored in their-well secured servers. Verification requests are always bogus in this case.

When you receive official messages from Yahoo, look for its purple logo to the left of the sender's name. This indicates to you the message came straight from the company, ending only with the address @cc.yahoo-inc.com, and not the scammers themselves. Messages from the scammers only have generic greetings (such as Dear Valued Customer, Dear Customer, etc.) while the ones from Yahoo address you only by your name. Remember you only get official messages from the company on an occasional basis.

As a friendly reminder, you're already using the current version of Yahoo Mail, as the classic one has already been phased out a few years ago. There are no upgrades currently available at this time. If one is available, it will be done automatically without your input.

Since you've clicked on the link in the message, you need to get a virus scan on your computer right away.

100% SCAM

1 - Yahoo will NEVER address you by a generic greeting like Dear Valued User. Official emails from Yahoo ALWAYS address you by your name

2 - Yahoo accounts ONLY expire if there has been NO activity on the account for more than a year. As long as you check your email or log into your Yahoo account at least once a year, it will not expire

3 - Yahoo would NEVER use an AOL account. If it's not from @cc.yahoo-inc.com or @yahoo-inc.com it's fake

4 - Yahoo would NEVER ask you to click on a link

You should run a virus scan if you clicked that link

No. Yahoo emails don't expire, and the link would probably install malware on your computer.