https://techcrunch.com/2023/07/31/apple-greenlights-twitter-apps-rebrand-to-x/

After weeks of changes to its social handles, branding on its interface, a redirect on the web, and lots of chatter from its owner, Twitter the app has finally changed its name on the App Store to X. The single-letter name may have an exception: Apple typically doesn’t allow developers name their apps as a single character.

Last week, Twitter rebranded its iOS and Android apps, replacing the old bird logo, and screenshots in the App Store, with the new ‘X’ logo. However, the company wasn’t able to change its actual listed name on the App Store. As developers pointed out, this is because the App Store Connect — the portal that lets developers manage their apps — shows an error when developers try to use just one character as the app name.