I had my iPhone time stuck at Cupertino. At first I was unable to Edit it. Later I changed my Date and Time to manual. Then I went back to Customize home screen. I clicked on the clock widget and again clicked on it on the screen. Finally it showed other countries. After that I changed my Date and time settings back to Automatic and now it is working fine, no issues. My Phone's firmware version is 18.1.1
iPhone Clock stuck at Cupertino.
These are the Developer Forums, where developers of apps for Apple's platforms ask each other for hints and tips on coding.
Your question is more of a product support one, so I'd suggest you ask it over at the Apple Support Forums. Thanks.