DO NOT respond to any mails which ask for Urgent Upgrade. Here is a sample mail which I just received.
There is a link called UPGRADE NOW.
DO NOT CLICK ON THIS LINK.
This link leads to an authentic looking Office 365 login page. Needless to say, it is a fake page. This is called a Phishing attack.
DO NOT put your password there.
Just delete the mail permanently and do not think about it again.
I have already informed the relevant authorities in Microsoft. They will do the needful.
If you are in another country or region, you may not receive this particular type of mail. But in any case, do not trust any such mails. If you are an IT person, go to the Office 365 Admin page and check if there is a genuine need for license upgrade. If you are not an IT person, just alert your IT team.