Actually, Apple would have to introduce the iPhone 7s and 7s Plus in September. Instead, there was a jump in the naming and the successor of the iPhone 7 was directly to the iPhone 8. Whether this step in the designation was justified or not, is an open question. With the first OLED iPhone Apple introduced then also the completely new designation "X".
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As Robert Cihra, a Guggenheim Partners analyst, now reports, Apple will call the cheaper LCD model just "iPhone", without any additional attachments and additions. Already with the MacBook and iPad Apple has gone this way, now even the entry-level model of the iPhone so simple to name, so would fit well. However, eliminating the number would make it harder for customers to differentiate between generations. For the 12-inch MacBook, this may not be so bad, Apple does not necessarily update the device annually. An iPhone, on the other hand, is actually equipped with new hardware every year.
The more expensive OLED model, on the other hand, will continue to carry an "X" in its name. However, Cihra is silent about how to name the larger version of this model. If Apple retained its naming, it would actually have a "plus" appended. As always, we will not know until the fall how Apple has decided and what models, specifications and labels are really being presented to the public.