Rcvd email stating to upgrade my att.net email within 48 hrs to assure receiving email

Received this email: 

Dear user, 

 This is to remind you that your AT&T mailbox needs to be updated within the next 48 

hours to avoid any interruptions in receiving new mail. 

Is it real?  Came from AT&T Account Management <[email scrubbed]>

Guess it is phishing, but just checking.