Online users who have received the fake "Your Mail-Box has reached an upgrade stage" email are asked to delete it because it is a phishing scam. The fake email is being sent by cybercriminals to trick the recipients into clicking on the link or button in it. But, the link or button goes to a phishing website that steals email and other online account credentials.
The "Your Mail-Box has Reached an Upgrade Stage" Phishing Scam
From: Mail Support <sjmasonryllc@hotmail.com>
Sent: Thursday, May 31, 2018 3:22:24 PM
To: Mail Support
Subject: Your Mail-Box has reached an upgrade stage.
Account Update
Your account may be closed on 02/06/2018
Dear Attn User
This message is being sent to you to inform you that your account is will to be closed at 02/06/2018
If you wish to continue using this account please upgrade to our services. Ignoring this message will cause the account to be closed
Update your account
Note: This upgrade is required immediately after receiving this message
Thank you
Account admin