Mr. Musk may have successfully pushed Twitter's new name and logo, 'X', and even made the vanity domain x.com redirect to the social media website, but that's not to say, the Mathematical double-struck letter will fit the bill everywhere. Apple's App Store can't accept Twitter iOS app's new name due to minimum character requirements
I’m guessing that probably violates some app store rule.
I’d agree. The two character requirement made for a hilarious one liner in the article though “he already has a company named SpaceX.”