Update Apple ID Settings
Update Apple ID Settings
What happened for me to get this.
More importantly, what do I do?
iPhone X
Hmmm... This document is the only one I can find along those lines If you are asked to update your Apple ID email address - Apple Support
What I would do is got to Settings on your iPhone X and see if there's anything with a red number or message next to it. That's usually how Apple reminds me there's something they want me to update.