Does Citibank (US) accept US citizens abroad?

To open a Citibank account online, including Citigold relationship tiers, Citi requires you to be a US citizen or US resident alien and to give a physical US address. So a US citizen living abroad with no US address can't apply online. Citi's page doesn't cover existing customers who move abroad. Citi's international offshore banking (Citibank International Personal Bank, Citigold International) isn't covered here; we found no official Citi statement on US persons for it.

"To apply online, you must be a U.S. citizen or a U.S. resident alien and at least 18 years old. You'll need to provide a physical address in the U.S."