https://www.cnet.com/news/after-iphone-xs-apple-still-has-an-icky-2019-iphone-naming-problem/

The second problem arrives when you think about the issue of succession. I've been saying for a while that the "X" is an important branding shift for Apple, one that represents a higher echelon of iPhone than the ones that preceded it. The X represents Apple's rebranded iPhone with secure infrared face unlock technology, no home button and state-of-the-art giant screens. The X brand is a pricier lineup than before, and it's easing you steadily, purposefully, into paying more for your phone.

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